Back to the basics — Scope tips: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • Reason for this report
  • What I won’t do!
  • Things to consider when mounting a scope
    • Consider the scope mounts.
    • Consider the type of scope
    • Consider the gun and where the scope has to fit
    • Pay attention to how much elevation your new scope needs
  • Summary

Reason for this report
This report is for a friend who recently acquired a new-to-him 30-06 bolt-action rifle. He asked me for some tips on mounting a scope and sighting-in the rifle, and I’m afraid what I gave him was a college-level course instead of the basic information he needed. Despite my “help,” he stumbled through the process, making many mistakes as he learned what I am going to try to tell you in this report.

This misadventure opened my eyes to a need for even more basic instruction about rifle scopes. If my friend is having problems, so are hundreds of others who read this blog.

What I won’t do!
This report will not advise you about which scope to get or even which set of features you need. All those decisions are very subjective and difficult to explain to someone who has no experience with rifle scopes. And, once you have some experience, you know what you want without being told. For example, if I were to tell you that low-power scopes are often clearer, someone would argue that his particular 6-24x scope is as clear as a bell. That’s because he uses only it at the rifle range on bright days. He has no trouble seeing the targets with the sun behind him. But he never mentions that fact when defending his scope. He just says it’s clear, and other readers are confused by the conflict between what he and I seem to be saying.

Or, if I tell you that you don’t need a mil-dot reticle to hunt squirrels, another reader will read on some forum where a shooter has had great success with a mil-dot reticle. What that forum poster doesn’t mention is that he only shoots the squirrels that are on his bird feeder, located 30 feet from his back deck. When I talk about hunting squirrels, I’m referring to hunting them in the deep woods, where a duplex reticle is the easiest to find against the dark green background.

One shooter wants a scope with a huge objective for better light transmission. Another wants a scope with a small objective, so he can mount the scope close to the bore line. This shooter wants long eye relief, that shooter wants variable magnification. There are just too many personal decisions when choosing a scope for me to cover, even in a series of reports. Scope choices are very personal, and the only way to find out about them is to start using different scopes.

I can, however, discuss how to mount a scope and sight it in. So, let’s start on that now.

Things to consider when mounting a scope
–> Consider the scope mounts:
1. Do they position the scope in the right place for your eye?
2. Can they be moved on the gun to accommodate the scope you want to use?
3. Will they attach to your rifle?

My friend didn’t consider this when he bought his first scope, and he ended up with a compact scope that didn’t fit into his rings when they were installed on the rifle. In his case, he used 2-piece rings; but because they attach to his Remington 700 rifle in only one place, they’re the same as the 1-piece rings that I often advise people to avoid. Here’s why:

Scope in rings
These 2-piece rings might as well be 1-piece, because they cannot be mounted anywhere else on this Remington 700 rifle. Obviously, they’re separated too far for this compact scope.

–> Consider the type of scope:
Compact scopes are great for some applications but not for all of them. If they can’t be positioned in the right place on the gun, they won’t present a full sight picture to your eye. A longer scope can be slid back and forth until the eye relief (the image you see when you look through the scope) is perfect.

–> Consider the gun and where the scope has to fit:
Some airguns don’t offer a lot of options for where the scope has to be mounted. Many Korean PCPs, for example, have a short 11mm dovetail on top of their receivers, so the scope mounts have to attach there. If the scope you mount extends out and interferes with the rifle’s rear sight, the sight may need to be removed. On some guns, that’s difficult — because, although the sight comes off, the base does not…at least, not easily.

Sam Yang 909S
This Sam Yang 909S is typical of many Korean precharged rifles: The place where the scope rings fit is a short strip of dovetail just above the receiver.

Sam Yang 909S rear sight
The Sam Yang rear sight is located just forward of the receiver, where a scope bell will hit it. The sight comes off easily, but the sight base does not. Be sure the scope bell will clear the base.

–> Pay attention to how much elevation your new scope needs:
Maybe this belongs with the sight-in discussion, but I’ll address it here. If you install a new scope and find that you have to adjust the elevation up to three-quarters of the scope’s limits, you’re going to have problems. Your barrel is pointing downwards in relation to your scope. You have what’s known as a “drooper.”

Most scopes will not hold a zero when adjusted up this far. The same holds true when the adjustments have to go too far to the right. Up and to the right are the places where the scope’s erector tube spring(s) relax and allow the tube to jump around from vibration. The erector tube is what holds the reticle inside the scope. It’s the reason why the crosshairs remain centered when you adjust them. The spring(s) work against the adjustment knobs, keeping the tube under tension and following where the knobs go. But when the spring(s) relaxes, the tube can move when the gun vibrates during firing or handling. I say spring(s) because some scopes use a single spring that’s set on a 45˚ angle to the adjustment knobs, while others have separate springs for each knob.

Summary
That’s it for this report. Let me know if there’s something I haven’t discussed that confuses you about mounting a scope. Next time, I’ll discuss sighting-in your scope.

203 thoughts on “Back to the basics — Scope tips: Part 1

  1. This is going to be a good series.

    I know you haven’t gotten there yet, but after making an adjustment, do you make a habit of rapping the turrets with either the handle of a screw driver or your knuckle to “settle” the reticle?

    That’s the way I was taught, and it really works.



  2. I shared a few videos with my Brother today for Adyn to watch. The first one was about using peeps and the second was using a scope for long range shooting He missed at least one deer this season because he couldn’t see it through his scope before Daddy had to take the shot. We need to find out what he’s seeing to see if the eye relief and parallax are properly adjusted, If not he’d be better off with open sights.



  3. B.B.,

    I was surprised by the topic, since there is so much info. here already. But, I am very glad you are doing it.

    Since you asked for “missing” and “confusing” comments,…..

    1)..How does one know what “3/4” out or up is, unless they (carefully) take the turrets through their full range? Making notes of turns and clicks as they go. Then, re-center at the halfway points.

    My Leapers has about 7 full turns elevation and only 2 full turns of windage. Leaper’s says their scope turrets come “centered”. I called and asked. Different scopes might have different amounts of turret turn range also.

    You may remember I did this, along with some optical “centering” exercises, and ended up with a broken windage turret. On my new scope, I just left things where they where at. First shots where about 3″ low at 41′, so I opted for a shim in the rear saddle under the scope. In the end, I got 41clicks elevation and 20 clicks windage adjustments from factory set.

    2)..So, (shimming) and (optical centering) are something else you may want to touch on.

    On a side note, I would recommend to anyone to take some measurements of the scope, rings and gun when doing a set up. This way, you can tell if the scope has moved in the rings or if the rings have moved on the gun. I’m pretty sure mine did, and I thought my set up was “perfect”. Now, I have a reference point from which to check.

    Since checking eye relief is a bit hard,.. measuring muzzle to front cap, or, butt to rear cap, will give you a (reference point) for eye relief adjustments.

    I look forward to future installments of this article. Thanks.


    • Chris,

      You count the clicks between the stops and then return to the adjustment. That’s how you know. If you have a good scope with target turrets the adjustments are easy to see, but with a cheap scope you have to count the clicks.

      What you did the second time was the right way to do things.

      No need for measurements. Just pit some whiteout (typewriter correction fluid) on the scope barrel at the ring. If the scope moves, you’ll see it.

      You don’t measure eye relief. You hold the scope up and move it back and forth, then when it appears right, make a gauge with your thumb and forefinger that spans from your eye to the eyepiece.
      That’s your “measurement.”

      B.B.


      • B.B.,

        Thank you for the comments. I’ll have to give the “correction fluid ” a try.

        Finding the “turret movement range, max./min” I got,..just a bit hesitant to do it. My Leaper’s has the “no-tool” knobs, but has no fixed marks (under) the knobs that would be an indicator of min./max. movement. It seems that most do not.

        You did not comment on “optical centering”,..(V-blocks, rotate scope, adjust until cross hairs remain fixed),…I’m sure you know it. You did however comment a while back that “no one does this any more”,..but did not really say why.

        I’m sure other readers have read of this and would be curious. After all, most people want to get the best from their scopes,..and if this is one way,..then why not do it?

        Also,I would like for windage adjustments to be “0” at different ranges, (minus wind of course). Left at close, dead on at sight in range, and right at further distance,.. is what I do NOT want. You know what I’m going for here. Any advice on scope set up to achieve this would be greatly appreciated. Fully adjustable mounts?

        Of course, shooting at different ranges, noting the windage “drift”, correcting it at those same ranges, (noteing that), and then,..in the future, repeating it, along with the corrections, for each given range..would be another way. Which seems MUCH harder than just fixing it, or at least minimizing this at the “initial set up”.

        Again, very interesting article and I am glad you are doing it.



          • BB
            Who was the pro’s that stopped doing that?

            Have any of them done tests to show what the differences could be?

            Maybe some examples would help people understand the differences and what is accomplished or not accomplished by doing it different ways.

            I know I read in the past how you showed how to do it with V notches cut out of a cardboard box.

            And you have talked about using a mirror in the past.

            So I would like to see how the pro’s do it if they have a good way.



              • Chris, USA
                I’m surprise Buldawg hasn’t said anything. He just went through all this installing scope on his 48.

                I know he don’t want to mention the mount he’s using but the principle is the same regardless of what scope mount is used.

                Maybe he will read and say.


                • Gunfunn1,

                  Does’nt want to mention the mount?,…you lost me there,…and must have missed Buldawg’s comments as well.

                  I just searched the P.A. sight for “fully” adjustable sights and the (only) ones are150$.

                  I do suppose those are the only way to solve the “left, on, right” issue as mentioned above.

                  Got an opinion? No Bridgeport,.. and the indicator thing,.(barrel to scope), was a bust. Too long of a reach.


                  • Chris, USA
                    That’s what I said Buldawg did not mention it.

                    Yes there is a way to make sure the reticle is centered.

                    Look through the scope and hold a mirror over the other end. I have had the best luck out side with bright light. You will see exactly if the reticle is centered.

                    I think you called it the ghost ring.

                    And Buldawg just did all this on his Dinz 48 for droop. So I was going to let him explain.

                    But also the mirror will allow you to center your turrets then sight your gun and see how much the reticle is away from center when you look through the scope again while holding the mirror up to the scope and looking through it.

                    He was able to shoot his gun and see how far from center the reticle was after sighting in.

                    Then if you have a scope mount or rings that are adjustable you can make the correction you need and resight the gun and end up with the reticle centered.

                    That way you know that the turret spring will be in the middle of its preload. And you won’t be to far away from the spring tension that causes the reticle to shift when you shoot.


                  • Chris, USA
                    I will not refute BBs comment that the pros don’t do it anymore as I am no pro but for a fairly new to air guns and very new to FT match shooting as well as RWS guns and there well known droop issues the only way to be absolutely certain you get the right mount to correct for said droop is by being absolutely certain the scope is perfectly centered when you shoot the gun to measure the amount of droop you are trying to compensate for.

                    The quickest and to me the easiest way is by far to optically center with a mirror which I have done on three of my scopes that are on my spring guns and it took a total of 5 minutes to complete it on all three scopes and you know for certain that the crosshairs are perfectly aligned and centered in the scopes. You need either a bright light directly overhead of where you do it or the best way I found is outside in bright sunlight. It worked very well and takes only minutes to accomplish and since doing that on the scope for my new to me RWS 48 I found that it shoots from 6 to 7 inches low with JSB 10.34s at 30 yards. It can be done with the scope on the gun as well.

                    I used this as a starting point for testing different mounts to get as close to dead zero or slightly above with the scope centered so that I would only have to adjust the scopes elevation turret very little and if any at all it would be in the downward direction so as to add tension on the spring versus lessening the spring tension while zeroing for the POI and POA to match.

                    I tried a RWS .025″ compensation mount and it still hit about 1 inch low, so I tried the UTG 17.1 inch compensation mount and UTG low rings that GF1 sent me of his to test with and it hit 10 inches high which tells me that my centering of the scope was basically spot on as with no compensation it hit 7 inches low and with the .025″ RWS mount it hit 1 inch low and the 17.1 inches of correction mount which is .060″ of height difference it hit 10 inches high. That tells me that I need a mount with approximately .030″ correction and I found a mount with .0295″ of correction so with that mount my 48 now shoots about 1/2 inch high at 30 yards with JSB 10.34s shooting at 877 fps.

                    So you decide if centering a scope is necessary or not and as far as the mount is concerned I am not allowed to say where it came from as I do not want to queer the deal.

                    BD


        • You did not comment on “optical centering”,..(V-blocks, rotate scope, adjust until cross hairs remain fixed),…I’m sure you know it. You did however comment a while back that “no one does this any more”,..but did not really say why.

          Unless one is using a ring/base set that allows for external adjustments, one is going to have to crank the elevation/windage adjustments off-center anyways.

          I think the classic Leupold ring/base system allows for windage correction using the screws on the rear of the base (the front is a very tight (===) dovetail — some companies actually sell machined steel “points” so one can get the front ring into perfect alignment with the rear ring before putting a scope into it… I likely have impressed grooves on my scope as I used a broom handle to rotate the front ring into what looked aligned, and then tightened down on the actual scope)

          WITH external adjustments, centering the scope and using the externals to do the initial zeroing would mean one has the full range of the scope for tweaking.


          • Wulfraed
            I mentioned the optical centering.

            That’s when I said BB cut V’s in a cardboard box.

            But looking through the scope with a mirror on the other end is real easy.

            You can go outside and check the scopes that you have mounted on guns right now and see where the reticle is in location to the scope housing.

            Try it and let me know how your scopes are mounted.


        • I should have read the rest before closing the previous reply…

          Also,I would like for windage adjustments to be “0″ at different ranges, (minus wind of course). Left at close, dead on at sight in range, and right at further distance,.. is what I do NOT want. You know what I’m going for here. Any advice on scope set up to achieve this would be greatly appreciated. Fully adjustable mounts?

          This is typically a sign that the barrel bore is not aligned with the scope bore.

          If one looks down on the top of my Marlin Glenfield 60c — I have an obvious example of this. Even the stock cut-out is thinner on the left than the right because the barrel to action join is cocked…

          \
          |

          scope is mounted on |, barrel is \

          I’ve shimmed [dr. scholl’s moleskin] the rings to help angle the scope to the left, but that leaves me with a triangle with the sides being receiver, barrel boreline, and (hypotenuse) scope boreline. Obviously the scope and barrel will only align at one distance.


      • I left the scope loose in the rings and an allen wrench in one of the screws and slid it back & forth ’til it was right, then hit the allen to lock it in place on my Regal and it’s the best scope mounting I’ve been able to pull off.



      • Chris, Sorry I got your name wrong. I been trying to share as few links as possible and still get done what I’trying to say but typing isn’t much fun anymore and I can’t explain it as well as someone who’s taught in a classroom environment
        Here’s that video I mentioned above:
        https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=video&cd=3&cad=rja&uact=8&ved=0CCkQtwIwAg&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3Dq886sc-2grk&ei=B7DiVPv-G8eWgwTDhoPgCw&usg=AFQjCNFS6z1serXCLdKYz5qGFy9ESzrqZA&sig2=aQXB8L2CS44dht1Vl_ld3A&bvm=bv.85970519,d.eXY



        • Reb
          I got the email you sent with the video link.

          That’s why scopes say how many inches of movement one click of the turret will give.

          Most say 1/4″ movement at 100 yards. But some say a 1/8″ movement at a 100 yards.

          The scopes that move a 1/8″ per click will give you a more precise adjustment when zeroing or doping your scope.

          What that guy did in the video is how most snipers adjust their scopes for a shot after figuring out their distance to their target and wind speed and direction.

          They don’t use hold over or unders. They just put the correct amount of elevation and windage clicks in to make their shot.

          After they make their shot then they count clicks back the opposite way to be back at the their scope zero that they sighted in at.



          • What that guy did in the video is how most snipers adjust their scopes for a shot after figuring out their distance to their target and wind speed and direction.

            They don’t use hold over or unders. They just put the correct amount of elevation and windage clicks in to make their shot.

            And some firearm scopes offer turret drums custom optimized for a particular round, so that, once zeroed at, say 100 yards, the drum readings are direct distance rather than click. Use a rangefinder, dial in the yardage on the drum, shoot.

            http://kentonindustries.com/faq/yardage-formats-defined

            Problem — you need one for for each variation in ammo… Can get expensive.



            • Baron Wulfraed,

              I just replied to Gunfun1 with a Kenton link, but looks like the spam filter binned it. 🙁 Yeah–custom turrets can get expensive!

              I’ve heard that U.S. snipers commonly dial elevation and hold for windage, but I’ve really not studied the matter. I think it’s tough to hold for both elevation and windage with most reticles and it makes sense to hold for windage–espeically with a spotter calling the wind. While the range to any stationary target is invariant, the wind is always changing and it’s faster to change a windage hold than repeatedly dial.

              Non-US snipers often work “solo.” They have optimized their techniques to be independent and expeditions, form what Victor Aguilar of “Sniper Flash Cards” has told me.


              • I still wonder just which military is ordering Leatherwood ART
                http://hi-luxoptics.com/index.php/riflescopes2/art-series/m1000.html
                scopes? I’ll accept that the design was created for Vietnam, but I haven’t seen any shots of troops equipped with one. I have an older Sportsman version for my HK-91. The older one predates the rage for mil-dot — I’ve got US and metric grids in the lower quadrants (US goes to 72 or 80 inches), along with short dashes on the cross hairs. For mine, one is supposed to range by adjusting the zoom until the target correctly matches one of the many sizing marks.

                This (cheap/chinese manufacture) scope is designed to adjust the tilt of the scope as one zooms. Drawback, unless one has the time to unlock the cam from the zoom, one can not use high power on close objects or low power on far objects. So no really usable for small varmints…





          • Gunfun
            That’s why I posted the link as it is explained much better than I can do as understand exactly what is explained it just not as easy to duplicate so the link is much clearer and through.

            BD


            • Buldawg
              I do believe that should be a basic first step to mounting a scope before its even placed in the scope ring.

              I would like to know why somebody wouldn’t do that first. And then they can tell me why not too.

              Maybe there is something I’m missing.


              • Gunfun
                I put the hawke scope on the 48 when I first got it and started sighting it in and it was grouping very well until I got about 1/2 inch above the POA and it started throwing flyers out everywhere. You and me texted back and forth about exactly what that link stated to do so I optically centered the scope which was at the top of it elevations travel thus the flyers it was shooting as the erector tube was bouncing around inside the scope when shot. Then after optically centering the scope and shooting for droop you see how that allowed me to determine which mount is best for the 48.

                Next it is the B40s turn to get tested as soon as I get my seals as I ordered some ARH problem solver seals for the TX and B40 since the other one I ordered still has not shown up so hopefully by weeks end I will have seals so I can do the test you told me to do to make sure the seal is working correct and install a new seal and see if the fps come up to where I want them then I can shoot for droop and determine which if any compensation it needs.

                BD


                • Buldawg
                  All those text you sent me with pictures of the shots taken with the different mounts you could probably put together a slide show video.

                  And you didn’t get that seal yet? You been waiting for a while now haven’t you.


                  • Gunfun
                    No it has not showed up so yesterday I ordered some from ARH and just now got tracking number but it does not show any info yet but its priority mail so they should be here Thursday. They are a set of two seals that are bigger and smaller than 1 inch so that one of the two should fit right and get my fps back up in the 800 fps area.

                    BD


                    • Buldawg
                      Did you take a caliper and measure the cylinder by chance.

                      I wonder if its right on 1″ or if it is over or under by how many thousandths.



                  • Gunfun
                    I emailed the vendor for the first seal last night and they said it is probably got lost in the mail so they issued a refund so I am glad I ordered the seals from ARH .

                    BD


                    • Buldawg
                      Lost in the mail?

                      I wonder if some of them places your dealing with are scamming.

                      ARH is a good place. I don’t know what the other places are your using. But sounds like you need to keep a watch on them.




          • Reb
            You will only have an issue if the guns barrel is not aligned well with the action or scope rails.
            If there is little to no offset between the barrel bore and action/scope rails it will never show its self with any decent scope. Since I was sighting in my 48 which are known to have bore alignment issues and the gun was grouping 1/2 inch groups at 35 yards at a 1/2 inch above the bulls and when I added more down adjustment into my hawke scope and the pellets started hitting everywhere I knew something was wrong since it was putting one on top of the other .

            That’s how and why I learned and found how to optically center a scope the easy and quick way and it can be done with the scope mounted on a gun. I use an old motorcycle 4 inch round rear view mirror glass so that it can be held up against the objective end of the scope while on the gun. it does work best out in the bright sunlight but any bright light behind the scope will work also.

            BD


            • I had to take back the 3-9×40 AO I got the other day. It came with picatinny mounts and the dovetail on my Airmaster is 8mm. I was gonna buy proper mounts for it but ran outta cash. I also bought a couple pairs of fleece lined jeans so I could get outta this ski jumper but the were too short and too big in the waist & they were 30×30’s which generally is my size. They were warm except on my ankles!I’ll get back what I need after the 1st. I remembered ordering the 2400KTand what it was gonna do to my finances for about a week.Still waiting on the email to say it’s on the road.


              • Reb
                You know UTG makes piccatinny to dovetail mount adapters that would have allowed you to put that scope on your Airmaster. They can also be used to mount it on your new 2400KT as well. Hope it goes out to you soon as I know you will like not having to pump up or break open a barrel just to shoot but the CO2 cartridges can get expensive if you shoot every day.

                http://www.ebay.com/itm/181650396867?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

                I think the jeans were sized wrong if they were that short and big in the waist. Its always best to try them on before buying to make sure they fit.

                BD



                  • Reb
                    The UTG adapters will only raise the scope about 1/8 inch at most and I have used them on several scope with very good success and they adapt from 13mm down to 8mm so they will work on your Airmaster. I understand the you want the scope as low as possible so just thought I would so you these as they are shipped free and that save 7 or 8 bucks.

                    BD


                    • I recently bought a pair of the UTG adapters and, yes, they barely raise the scope at all. Actually, if one is looking for the lowest possible mounting of a scope on an 11mm dovetail, I suspect that the lowest available Weaver/Pic rings (Weaver “Top-Mount” low rings, as one example) fitted to the UTG adapter might result in lower scope height than the lowest available 11mm rings! Even the lowest 11 mm rings are not very low.

                      The one potential fly in the ointment is the UTG adapters might not fit on some rounded receiver / top surfaces. They are very thin and there’s not enough relief to accommodate a tight radius of curvature beneath them. They fit best on flat surfaces. Perhaps UTG will develop a thicker version of the adapter someday with relief for rounded receiver tops. I should have asked Leapers/UTG VP, David Ding, about this possibility at SHOT. Maybe B.B. can ask him to consider it, but I also think the very clever adapter design would need to be fundamentally modified a little.


                    • I really liked the scope but ran outta funds so I returned it with the intention of getting another after the 1st but my 2400KT will be here any day and that may change things considerably, also I’m moving into an apartment and will have to travel elsewhere to be able to shoot outside.
                      I liked what I saw about those adapters and will probably get some on order before considering another firearm scope purchase.

                      Reb


                  • Reb
                    If you can get a scope that comes with dovetail rings that would be best, but if that is not possible then those adapters are a very good alternative .

                    Best of luck with your new 2400KT and don’t shoot your eye out LOL.

                    BD



  4. BB, I recently had a problem with mounting a scope. I was trying to put a scope on a Daisy 853, which normally I shoot with a diopter sight (not the original one, but a aftermarket sight). For some reason, I could not shoot better groups with the scope mounted on this rifle, as I could with the diopter. I am blaming my head position for that, as I feel that the diopter did force me to look through a very tight hole and maintain my head better aligned than the 4X scope I was putting on it. Or maybe it was just parallax error on the scope and I didn’t notice. Fact is, for the very first time in my life, I removed the scope and returned to an iron sight which gave better results. Ever happened anything like that to you?


    • Fred_BR,

      Yes, it has. And I think you are going to be surprised. I believe you have reached the accuracy limits of your rifle! The scope could do no better because the peep had already taken the gun as far as it will go. What do you think?

      B.B.


      • I agree. The best group fired with the diopter was .57 inch, in a very horizontal group, with just one shot to the right not touching the rest of the “one-hole group”. If I discount this one shot and measure the remaining 4 shots, it’s only .335 in. This was, of course, shot at 10m from a rested position, with RWS R10 Match pellets.
        The scoped groups are about .85 in, nicely spread over the center of the target, and no matter how I shot the rifle, it never got any better. What I expected was that the scope would, at least, repeat the results of the diopter, but it didn’t.



        • Fred,If you were further back you’d probably notice some improvement I was shooting my 953 @ 45-50 yds this summer and I’m sure the lack of magnification woulda been a handicap if I had been using peeps.


          • Tom and Reb, this weekend was raining a lot here (thank God, because we are under a severe dry season), so I could not go to my gun club. My idea is to compare the results of diopter x scope at 10 and 25 meters. I can shoot to 50 meters, but I don’t think the 853 will be a good platform to shoot at longer distances. I will share the results with you guys.
            Like you, Reb, I also expect that the magnification is going to help me to see distant targets better, but I don’t know if the resulting groups will be actually tighter.


  5. Hi everybody…

    Great article!

    There’s one thing I would add:

    Stay away from scopes until you have at least some experience with shooting and know your rifle well enough. You don’t have to be a world champion, but have some basic understanding of how it all works.

    Otherwise you will be trying to fix a problem (you’re not hitting the target) without knowing the cause. Maybe your rifle doesn’t like the pellets you’re using. Maybe you’re holding it wrong. Maybe you’re jerking the trigger etc. etc.
    The added complexities of scopes won’t help at all in this scenario.

    I have a € 40,- Leader 4×32 on my Diana 31. I first I couldn’t really get it to work, but now that I have some experience with the rifle and with shooting in general, I find that it’s really an ok scope for what I do (indoor shooting at 9 meters).

    I surprised a friend when I told him I could hit 6mm airsoft balls at that distance from a rested position. He was even more surprised when he managed to do it himself 🙂

    Kind regards,
    Stephan



  6. To All
    I was taught by my father as I am now doing with my grandsons that you need to learn to shoot a gun as it comes with open sights first to find out if there are issues with the gun itself just as Fred _ BR had already stated and proved to himself.

    My two grandsons had to become proficient with the open sight on their pellet guns first to the point that they could hit paintballs at 15 yards and then they were upgraded to diopter sights and learned to shoot even better with those especially since we have one of the two CMP Olympic 10 meter ranges right here in town and you can shoot your own gun provided they are 600 fps or below. They use electronic scoring for the targets so you can see exactly where you hit within a .177 inch margin which is a perfect 10.9 score if you hit dead center of the bullseye and once they were capable of hitting in the 10 ring repeatedly is when they get to be upgraded to scopes on their guns.

    It gave them a much better understanding of how to shoot a gun with the sights provided with the gun and as they were given better sights as I truly like diopter sight for 15 yards and under they had a much better appreciation of what a scope did for them and why it is used on a gun to start with and I hate to say it but with their young eyes they are now better shots than I am which lets me know that the way I was taught by my father and how I taught them is truly the best approach in my book to make better shooters at a young age. The interest and excitement that they showed with every step they made to becoming better shots makes all the effort and sometimes frustration on both are parts well worth the time it took to get them to the point that they are now and will only continue to allow them to improve their skills and marksmanship further so that when the new CMP world class firearm range opens here in the end of march I can feel much more confident and relaxed that they will do equally as well with firearms at the range as they have with air guns to this point.

    I am also looking forward to the new range opening as it will accommodate any type of firearm shooting there is that can be done with a 600 yard rifle range, 100 yard pistol range, skeet and trap ranges all with electronic scoring so you know right after your shot where you hit and can adjust your sights to correct and sight it in to nearly perfect bullseyes with every shot.

    BD



      • Reb
        I was out hunting with my dad at age 4 and by 8 years old I was turned loose with a 12 ga shotgun that I cut grass all summer to buy with my own money from my grandfathers sporting goods store in Grafton West Virginia in 1964 and still own that Remington model 1100 that is now one of my home defense guns.

        I actually had the shotgun before I got my first pellet gun which was the 1968 Crosman 1400 I still have today and still shoots like new and looks new as well although I have modified a new steel breech to fit the pump tube to accept a 24 inch disco barrel so that a scope could be mounted easily on the gun.

        BD



  7. It was 15F outside with 15 mph wind the first time I went out to stand the trashcan back up. It’s now up to 18 with 17 mph and I saw snowflakes when I went out to reset a breaker. No sense in opening a window to shoot out of in this wind!
    BRrrrr!!! From deep in the heart o’ Texas

    Reb


  8. Speaking of scopes…

    How much of a scope killer is the FWB300S really, in your experience?

    The system does, of course slide back, but it has to come to a relatively controlled halt, otherwise the shooter would probably feel recoil. I wonder if this is really worse for the scope than the violent jerking of a regular springer. Maybe it also helps that the FWB is not a magnum-powered gun.

    I’m thinking about putting something like a Nikko Gold Crown Airking 3-9×42 or 4-12×42 on it.

    Those scopes are still affordable and seem to be well-made.
    They also seem to be useable for short (~10m) to medium (25m) distances.

    The question is whether they can take the beating.

    Any input would be appreciated 🙂

    Kind regards,
    Stephan


  9. Anyone had experienced mounting a scope on a b3 under lever rifle? I have rings that fit the grooves in the receiver but I don’t know if I can tighten them enough to stop them from moving under recoil. Thinking about putting a small strip of metal between the first ring and the cap at the end of the receiver. Also, has anybody had experience with the Winchester 4 x 32 AO scope? It”s about all the money I have to spend on the scope right now. Thanks for your help.

    Brent


    • If you’re willing to open it up you could drill a stop pin hole anywhere you want, clean out all the filings and that old fryer grease they use, soak the sealin 30w Non detergent oil and lube the spring with moly & it’ll be better than new. That would require a spring compressor but I built mine on top of my workmate and used a screw-jack.


    • Brent
      You do not have to take the gun apart if it is shooting good now to drill a scope stop hole in the top of the receiver. Assuming you have scope mounts with a stop pin in the rear mount just mount it on the tube where you want it to be at and take either a small center punch or anything that you can put in the stop pin hole with the pin out to mark the location on the tube to be drilled for the stop pin . Then with the mount removed center punch the center of the mark you put with either a punch or pencil or whatever you can get to fit to mark the pin location on the tube. Then start with the smallest drill bit you have and just drill enough to leave a nice dimple but do not drill all the way thru the tube, then start going up in sizes of drill bits until you are at the size you need to allow the stop pin to fit in the top of the tube but still not drilling all the way thru the tube. When you are at the size drill you need to fit the pin diameter coat the drill bit with a very heavy coating of the thickest wheel bearing grease or any other thick grease so that you cannot see the flukes of the drill bit and finish drilling the hole thru the tube. The grease will capture all the metal filings and prevent them from getting inside the tube and spring cavity. Just take your time and go slow and there should be no metal; inside the gun with no need to disassemble. Try to only go deep enough to just cut through the tube and not let the bit grab at the end of the hole and be dragged deep into the tube. You can put some electrical tape around the bit so that it will only go so deep or use a drill stop guide if you have one

      I have used this trick on cars and bikes for 45 years when drilling out broken bolts or new holes without the need to disassemble the item to clean out the metal from drilling. Just use the thickest grease you can find and coat the bit completely with the grease and take your time when drilling the final last part of the hole.

      BD


  10. Buldawg has a couple B-3’s, I don’t know if he’s put a scope on one or not but I had a 4×20 on my QB-36 but it has a stop hole for the rear mount. When I got it the stop pin wasn’t in the hole and it threw flyers everywhere but once I got it on right it shoots 1.25″ groups @25 yds.

    Reb


  11. @BB: Thanks for the info. I might give it a try then 🙂

    @Brent: Those cheap 4x32s all look suspiciously similar, no matter if they’re made by Umarex, Weihrauch, Winchester or whoever 🙂
    My “Leader” looks like that as well and works ok on the Diana 31 as long as the rifle has the “regular” german spring. The B3 seems to be in a similar power category (~ 550 fps) so the scope might work on it. Maybe you can use a stopper block or some kind of scope stop pin for keeping it in place. I don’t know what your scope rail looks like.


  12. Hm, now that you mention it, are one piece mounts better than two piece or is it the other way? I’ve always used two piece although I’m not exactly sure why. I would expect one piece to be more rigid but two pieces give you more flexibility in fitting the scope to the rifle. I feel so fortunate with scopes that work at 5 yards where they must be at the very top of their elevation. Leapers all the way!

    B.B., so the cheap price of the Marauder shows up in relation to the higher build quality of the Air Force guns. And that is interesting about the Lothar Walther barrel. I had supposed that the choke design on the Marauder allowed it to cancel out the build quality along the length of the Lothar Walther barrel by grabbing accuracy right before the pellet left the muzzle. But I suppose it doesn’t quite work that way. And how does the world class Marauder trigger compare with the Air Force triggers which some people found reason to complain about long ago? Anyway, I am so glad that Crosman priced the Marauder as they did since I would probably not know the difference between its performance limits and something better.

    Speaking of Lothar Walther barrels, it turns out that they make a replacement barrel for the 98k Mauser. Maybe because it is all German technology. Imagine a relatively unused 98k Mauser such as the surplus guns that come out of Yugoslavia. Rebarrel it with a Lothar Walther barrel. Reproduce the minimum headspace technique for fitting the barrel used on Savage rifles. Stone that trigger to perfection and mount a scope. Would that be a fun project or what?! And maybe not even that expensive.

    Matt61


    • Matt,

      I think you are jumping to conclusions that aren’t there. The Lothar Walther barrels in AirForce guns are choked, just like the barrels in the Marauder. They are just better barrels, overall. And that is a large part of what puts the average Talon SS ahead of the average Marauder.

      Regarding triggers, the AirForce trigger is quite improved over what it used to be. But as nice as it is, it isn’t adjustable and the Marauder trigger is, so the Marauder gets the credit in that category.

      B.B.



    • Thanks Edith! I just shared a video of my nephew’s first shots with a Mini 14via email and didn’t even think about someone else not being able to access it because it was originally shared on FB



      • Reb,

        The blog belongs to Pyramyd Air, and so our site will not be linked here. However, we’ll occasionally direct your attention to Tom’s site, as we feel there may be some things you’ll want to see. I still have to upload all the SHOT Show videos, which I cannot find on YouTube, although I uploaded the darned things myself for Tom’s Google+ page. You can see them on all his social sites, but they’re like needles in a haystack on YouTube. So, I’m going to create a YouTube channel for The Godfather of Airguns, and all videos will be available there as well as Tom’s website.

        I have a huge list of things I’m going to add to his site, including a logical list of educational blogs that are hard to find through the regular blog search facility. I know his site is dirt simple and not going to win any awards for design; but you can easily find what you want, and you don’t have to jump thru any hoops. No fancy graphics. Just hardcore airguns.

        Edith


        • I think it’s great! I believe in Keeping it Simple. and I’ve conducted all kinds of searches looking for stuff though the blog search facilities and Google and you’re right about the needle in a haystack, that’s why I like to link stuff in my comments so I know people will find what I’m trying to show them instead of sifting through a buncha junk like it took me to find it.
          Good Job!



        • Edith:

          Great job on the web site. Great pictures from the shot show.

          Question about the Texas Airgun Show on 08/29/2015: Google Maps shows it as about a 6 hour drive from my house. I have never had the chance to attend an airgun show. Is it worth the cost of the drive and hotel room to attend?

          Thanks,

          Jim


          • Jim,

            Absolutely! Lots of chances to see tons of airguns, shoot guns on the outdoor range, buy stuff you need and/or ogle the tables. Even better, we expect to have another full day with lots of giveaways and door prizes. People who came, stayed. When the show was over, many didn’t want to leave. At the hotel the evening before, they have a nice mixer with soft drinks and snacks. It’s possible there could be another fun event happening at the hotel the evening before the show. It’s still in the development stages now.

            Edith



              • Jim,

                I don’t have the name of the motel on the announcement because no arrangements have been made for 2015. But I expect the same motel to be used this year. Here’s the info from 2014. Special rates were offered for show attendees:

                Best Western
                Cutting Horse Inn & Suites
                210 Alford Drive
                Weatherford, TX 76087-4423
                817-599-3300

                Tom also stays at the motel the night before because he gets a little crazy before a show & I’d like him out of the house so he can chill. Besides, this gives him a chance to socialize with other airgunners. I’ll drive up the next morning.

                We’ll definitely announce when all the arrangements have made for the show. We expect to have everything in place by May.

                Edith


    • Edith
      A very very wonderful site you have created for us non social old geezers. I thoroughly enjoy getting a much better look inside of a shot show and could only imagine that I would be like a kid at Christmas and would never want to leave at least until I was broke and maxed out all my credit cards.

      I could only go if I left all forms of currency at home as I would most definitely have no will power.

      Most excellent indeed and keep up the great work as I for one truly appreciate your hard work and dedication to bring us this deeper look into the world of SHOT shows.

      BD


  13. The FWB-300S gives scope mounters a problem that other air rifles may not. If you get too long of a scope, you will have loading problems. Then you have to mount it higher, which then hampers the scope, by being further above the bore. I put a Burris Compact 4-12×32 on my 300S and by the time I got it adjusted to my eye, the objective covered the loading port to such an extent that loading the gun is harder, not impossible, just not convenient. Less eye relief or a shorter scope or possibly higher mounting all come into play or getting the scope mounted right on this rifle. Something to consider for all scope mountings…


    • JCK
      I got a Hawke 2.5-10 power Varmint scope own my 300s and its got about 2″ of loading room in front of the scope.

      Its not bad to load but the bug buster scope that was on it before the Hawke scope made for a lot of loading room.


  14. Mentioned it before, but since we are on scopes,..I thought I would repeat it…..

    I you have a UTG mount with the removeable clamp on the bottom/side,..you will see that the the “bar” has two points.

    The longer point, (which comes mounted in the down position), is for 3/8″ dove tails.

    The shorter point is for 11mm. dovetails.

    So, flip it or don’t, depending on what you got.

    This is per Leaper’s, via a phone call.


    • Chris, USA
      I do believe I mentioned that before. And there are other brands that can do that also.

      Of course I can’t rember of the top of my head. But the description usually say’s.


  15. BB,

    You were looking for input questions.How about including info on the use of scope stops and offset mounts and the like after the more basics?A case in point.I find I cannot mount my included scope far enough back for use on my Gamo Whisper.If you look at a picture you’ll see that the one piece mount has to stop at the big stop bolt Gamo used in the special rail on the receiver.Also,the special rail does not even go back all the way on the receiver.I have to strain my neck to just glimpse through the scope.

    We will always come up with a slightly different problem that may seem new when mounting scopes,but maybe you could come up with a representative tough one .Then by solving it you could arm us for many of our own problems,

    Another question.After I have my diopter set,isn’t my smallest parallax error going to occur for me ,at whatever distance ,when the image seems in best focus;no matter what the scales on the scope may read?And couldn’t that position change if you used my scope and fixed the diopter for yourself?

    Tin Can Man


    • TCM,

      That is what happens when a 20-something marketing person selects a scope to bundle with an airgun. They aren’t shooters themselves and they have no appreciation or idea of what is involved with mounting a scope. All they know is that the scope they select is their least-expensive SKU and they cannot sell them.

      The eyepiece adjustment that you are calling the diopter doesn’t focus the scope. It only focuses internally, so the crosshairs can be seen best. If that also clears the image downrange, it does so by coincidence. So parallax adjustment is still required.

      Your analogy is like telling someone to keep their car fenders between the turn signals as a means of guidance, instead of watching the road.

      B.B.


  16. Gunfun
    I have not took it apart yet as I wanted to have the seal I was going to use when I tear it down so I only have to do it once even though its a piece of cake to get apart. So it will be apart and measured and tested by this weekend since I know the ARH seals will be here by Thursday and I will let you know what the chamber measures and if it is out of round or tapered at all.

    Then a light hone to break the cylinders coating just like an engine and it should be as good as new. The seals are between .995″ to 1.030 inches in diameter and one of the two should fit correctly.

    BD


    • Buldawg
      5 under and 30 over. Well that will be interesting to see what the cylinder measures out at.

      And what did you call those ball hones? But yea I used one to break the glaze off that 300s and gave it a little cross hatch and it sealed the 300s up real nice.

      Let me know what you find.


      • Gunfun
        its called a dingle berry hone as it looks like those little round pine cone type balls that fall off of trees that hurt your bare feet to walk on and yes it will be interesting to see what it measure out to and I am thinking of possibly taking the front transfer port nut out so I can hone the complete length of the chamber, but it just depends on how tight it is and if it comes loose easy or not as I don’t have a tool to hold it properly.

        I can make one if need be as it an easy tool to make and just like what we used to hold fork tubes from rotating at Harley.

        BD


        • Buldawg
          We use them clamps at work to hold cylinders too.

          Basically a split collar the diameter of the cylinder then ours has two tangs that you put in a vise and tighten. Holds real nice with no damage to the cylinder.


          • Gunfun
            Yea its basically thing same thing only we made our out of a 3 inch square block of aluminum bored to the correct diameter the just cut one slit in the side so that you place the tube thru it and clamp it in a vise and the slit allows it to collapse around the tube without damaging the tube and gives almost 360 degrees of contact surface with the tube.

            Here at home I will use a piece of PVC or plumber pipe of the right ID and just cut the slit in that to clamp in a vise to keep from rotating. when removing the transfer port nut.

            BD


          • Gunfun
            I don’t know if my first response got caught in spam or not but I am replying again.

            It is exactly what you use only we made ours out of a 3 inch square blocks of aluminum by boring the correct size hole for the forks we worked on being 35mm, 36mm, 39mm, 41mm, 43mm and 49mm and then just cut down the side to make a gap so that when slid over the fork and clamped in a vise it had almost 360 degrees of contact with the tube and worked very well.

            I will use some PVC pipe or plumber iron pipe which ever I have or can find that fits the OD of the compression chamber and hold it without marring the finish .

            BD




              • We had a similar setup for our ram-swedge but it was to keep the pipe from sliding as it was swedged up or down. I used it when I wanted to be able to slide one pipe into or over another more than an inch and when used on a f150 muffler neck the job could easily be cut down and replace in about 10 mins. One of my coworkers always wanted to use the cheaper mufflers that had the necks bumped out for their whole length until he saw me do that.at a cost of $15 in his pocket


  17. Buldawg76,

    Thank you for all the info. and the link. I read all of your post in this blog. In fact, saved the entire blog (and) link,… to “favorites” for further review.

    The link writer cautioned against going all up and all down on turrets, as you may get stuck, and not be able to return. I found that interesting.

    I missed that you are getting into FT. I wish you the very best of luck! Quite a bold endevor.

    Unless I miss-read, I believe you stated the only way to truely correct for the “left, on, right” issue is to have fully adjustable mounts. Is that correct?

    Thanks again, Chris


    • Chris,USA
      Yes you are correct that in order to correct for right or left error you need a fully adjustable mount and they are made but very pricey and way to much tedious work for me and in most cases you will have plenty of windage adjustment to compensate without using up the total range of adjustment. My 48 when I got the right mount on it was hitting 1/2 inch high and 1 1/2 inch to the left but I had a 25 mph gusty winds from the right that day also so I was not concerned about the left hitting impact as it was most likely from the wind. both other test for droop were with in a 1/2 inch of the POI for windage.

      B-Square makes a fully adjustable mount for elevation and windage but to adjust for elevation it must be removed from the gun to adjust then put back on and reshot, the scope does not need removed from the mount unless you use the scope stop pin as you cannot get the mount off with the pin into the hole in the gun and I was using the stop pin so I did not want to have to keep removing and installing the mount and scope, plus it is over 80 bucks and to rich for my blood.

      Hawke scope also make a fully adjustable mount the can be adjusted on the gun and is a better design as far as adjustability from a being mounted stand point but only has two 3/4 inch long contact mount points to hold the mount to the gun and has a stop pin but then again is to pricey for me it is part number HM 6170 for the 1 inch mount . If I was going with an adjustable mount it would be the one to buy but I prefer one piece fixed mounts as they cannot loose their adjustment at all.

      BD



      • Reb,

        That posting went to the spam filter, which marked you as a spammer. When that happens, some of your other posts may be caught in the filter as well.

        Posting links to other website is telling the spam filter that you are potential threat.

        B.B.



  18. Guynfun
    It was off ebay and the seller is called customseals out of Australia and has a 99.6 % rating so I new it would take a while to get here but yesterday was 30 days and that’s just to long. But I got my money back so its all good and the ARH seals are on the way and I have a tracking number for them it just has not been tracked for the first time yet.

    I may still get the seal from Australia any way so we will see about that but the money that they have already refunded to me will pay for the ARH seals.

    Ebay does have a good buyer protection policy so if you don’t receive an item they will get your money back.

    BD



      • Gunfun
        Yep I will text you a picture of them as they are supposed to be two different material seal and one is a Tesla seal and the other is a Apex seal. I am not sure of the difference between the two but with them the Vortek seal and o ring and the Crosman seal plus the OE seal I should have one that will fit right and pass your suction test. It maybe that I need to add some weight inside the piston like the guy that did the tests on the MKI and MKII with the Vortek and Maccari seals and springs found that a heavier piston gave a slightly higher fps number but them it also increased recoil so I hope I can get the fps without having more recoil as well.

        BD


        • Buldawg
          Yea let me know if that seal will bleed by when you put your finger over the transfer port hole and try to pull the piston out from the forward position. Of course when you have it out of the gun.

          It should act the same as if you put your finger over the hole of a syringe. What ever distance you pull away when you let go of the piston it should suck back down towards the transfer port.

          Thats how we test umbrella seals at work on hydraulic and air cylinders. If it works the opposite way like I said to test it for sure seal when used the right direction.

          And the only thing I can say is that weight placement can help in one way but hurt in another. If the piston side was weighted then that should make a harder forward hit on the shot cycle.

          That’s just something you will have to experiment with your gun and your pellet choice.

          You know how that goes. It can be thought that it will work one way and turn out another way when its tried.

          If you mess with it let me know how it works on your gun.


          • Gunfun
            All very good points and as you said there is a trade off for everything you do so I would prefer to keep it like it is with very little weight inside the piston and almost zero preload to keep it with the light recoil it has now but just want to be close to 800 fps with the 10.34 JSBs.

            hopefully I will find the seal in it now is not sealing good and one of the new ones will make the difference I am after am I will be on to checking for droop and correct that then be able to have two good FT spring guns to choose from.

            I will let you know what it turn out to be and the combination I use in the end.

            BD


    • BD,

      just got off the phone with my father-in-law. The transmissions that he and a bunch of other grease monkeys used to convert from a 2 to a 3 speed was in the Oldsmobiles. He can’t remember the GM name but it was the same trans used in the Pontiac and the Caddy. However, we are talking early 50’s! They would access the throttle body and remove a plug. The transmission was built with 3 speeds including the clutch pack. He noted that the trans for the Cadillac did not have the plug and was a 3 speed. Also, the engine had to idle at 1200 rpm until the plug was removed. Then the engine would idle at 600 or 700 rpm? He didn’t state the exact speed. This was the case for only a year or two and then GM stopped this practice but he said there were so many transmissions out there that he made very good money on the conversions.

      Fred DPRoNJ


      • Fred DPRONJ
        I started working on cars in 1976 at an independent shop so we worked on just about anything that rolled on four tires and my boss/owner could have told me exactly what trans that was and I don’t doubt that they made one with that design although I never worked on one or if I did I was not aware of the mod that could be done. It is likely that by removing the plug it allowed the trans to utilize the passing gear feature that most GM trans had when you stomped the pedal to the floor as it would apply the second gear band and also apply the high gear clutch pack thereby in essence giving you a gear ratio that was in between second and third so while it was a three speed trams it could be made to have an intermediate gear by applying the band as well as the high gear clutch pack which would cause the middle planetary cluster to rotate around the outer shell and create the additional ratio to allow the vehicle to accelerate faster than if it was dropped to second or kept in third.

        So again I am not 100% sure but by removing the plug from the valve body it may have allowed the trans to utilize the passing gear ratio as a full time second or third gear.

        BD


      • Fred and Buldawg
        GM used a transmission in the early 60’s to the late 60’s that was called a switch pitch on the later turbo 400 wich was a 3 speed. And the early trans was a 2 speed based on the poweglide.

        They both used a valve body that changed the fluid passage electronically by a switch mounted on the accelerator pedal or on the carburetor throttle linkage.

        The torque converter had a variable vane that increased or decreased the stall of the transmission. In otherwards the car would start moving at lower rpm. If you pushed the switch it would give you a stall speed racing type converted. If the button was pushed you could take off at a higher rpm.

        I had a 64 Skylark that had the 2 speed version. And Kenn Bell Buick offered different converters for racing. You could get a normal 1200rpm in the low side up to 3800rpm stall on the high side if the button was pushed or the switch was flipped depending how you set the switch up.

        But that’s how they got the later name of switch pitch tranny’s. Oh and I forgot I had a 69 Buick Riviera Grand Sport that had the 3 spd tranny.

        Maybe that’s the tranny that your talking about Fred.


        • GF1 and BD,

          I started to do some research last night and Wikipedia refreshed my memory. In 1952, GM had a tremendous fire loss at the Livonia, MI plant which made the Hydra-matic transmissions. GM had to scramble to supply trannys to those cars that used the trans and ended up using whatever they could get. Now it gets fuzzy as I believe they must have blocked off the 3 gear trans to sell in those cars that people only wanted to pay for the 2 speed, which I guess was standard equipment back then. My father-in-law said it was pretty silly what GM did. He didn’t know why and then we are talking about 62 years of time passage. As a former fire protection insurance professional, even I forgot about that GM fire which I had learned about early in my career and that was only 42 years ago! This situation only lasted for a short while – I suspect 9 months – because that is the amount of time it took GM to get another plant up and running to produce the Hydra-matics. Anyway, this was all in the 50’s.

          And now, back to airguns.

          Fred DPRoNJ


  19. B.B., You’ve made some great points about personal preferences and needs in evaluating and selecting scope features here. I’d like take this opportunity to contribute a finding that I’ve made using my “optics lab in a pocket,” (a Leopold Zero-Point instrument originally designed to be a fancy bore-sighter) to your blog. I’ve also used a solid gun sighting vice and a bench at the range, but the Zero-Point works better for finding scope mechanical and calibration deficiencies.

    I don’t recall if I described my “mission” to you at SHOT, but I sampled at least one scope from nearly every scope manufacturer’s booth at SHOT– from the least expensive Asian brands to the most expensive Hensholdt. I evaluated the samples to detect the presence of parallax adjustments coupling to reticle position against a target in the view finder (reticle shift or what I call “wandering”). Such coupling, alone and apart from parallax error, causes point of impact shifts and error on targets.

    With any given scope, I believe it is ideal to be able to move the parallax adjustment throughout its travel range while suffering far less reticle movement (error) than than the movement provided by a single “click” of the scope’s E/V dials. (The error induced by making a parallax adjustment should, ideally, be significantly less than the level of precision offered by by a scope’s E/V dials.)

    I can easily discern a 1/4 MOA shift in a reticle with my Zero-Point. Out of dozens of scopes I’ve evaluated, I can count the number of parallax adjustable models with non-discernible error on one hand! Also, ALL of the AO scopes (the kind where the objective lens moves back and forth when you twist the objective bell–as opposed to side parallax/focus) cause the reticle to move in both elevation and windage by at least about one MOA (and usually much more), as the objective is dialed from its minimum range setting to infinity. The path of the reticle usually tracks the angular motion of the objective bell. (The reticle follows an circular arc against the target/image that subtends the same number of degrees the AO adjuster is rotated.)

    I have found only a very few scopes (all side-adjust models) that exhibit no detectable shift–and even then, different samples of the same manufacturer’s product SKU often produce different results, which implies that reticle coupling to the parallax adjuster can be a manufacturing problem! However, the better side adjust scopes typical feature under an MOA of error and the error typically lies entirely in elevation. Elevation-only errors can (and obviously are) accommodated by shooters with elevation “dope.” The parallax adjuster-induced errors just get “buried” in a shooter’s proven holdover or elevation dial adjustments.

    The circular path of the AO style parallax adjusters (again, I refer to scopes with a movable objective as “AO”) is nearly impossible to deal-with over large adjustments. I will now never use an AO scope over more than about a quarter of its angular adjustment range–depending on the error I measure in the scope and my accuracy needs. I don’t shoot field target competitions but, if I were using an AO scope, I think I would range with the AO, as most FT shooters, but then return the AO to a known “acceptable” error range for taking the shot, and I wold accept some blurriness in the image for the shot, if necessary. I would also make sure that I had a good cheek weld and consistent eye position (eye centered on the optic axis of the scope) to reduce parallax error. At least a shooter can minimize parallax error with consistent eye position; the reticle “wandering” induced by turning an AO over a significant fraction of its range cannot be moderated to an insignificant level–at least based on every AO scope I’ve ever checked for this problem.

    It was very interesting to see the reaction to my experiments and findings at all the scope manufacturer SHOT booths. Most of them accepted my findings of imperfections in their scopes fairly gracefully after I took the time to address their initial questions or objections, but some did not. I’ll call one out company as being exceptionally interested in my findings. I had a conversation with Vortex prior to SHOT, because I originally found the problem in a Crossfire AO scope. Not only did Votex conduct their own investigation that confirmed my findings, but they also recommended looking to side adjust mechanisms to limit or eliminate this problematic source of error. Vortex offered to take my Crossfire scopes back for warranty service, but I think it’s nearly impossible to align a rotating objective lens perfectly square with the optic axis of a scope. It doesn’t take much “tilt” at all to make the reticle shift. The lens also must be ground perfectly in circular symmetry. I suspect the problem lies more in the realm of lens alignment, however.

    The potential error mechanism in a side-adjust adjust scope is different from an AO scope, and I won’t get into the details here, which I’ve discussed at length with Vortex techs and, again, all the “perfect” parallax adjusters I’ve encountered have been side adjusters–including my expensive Vortex Razor 5-20x scope and a few other moderate to high-priced scopes.

    BTW, I have a new idea for implementing my scope epoxy bedding practice that most anyone can accomplish, I think. I’ll take some photos and submit a guest blog to you for your evaluation to see if you agree with me that it might be appropriate for your readers.

    -Cal




      • Thanks, Gunfun1. I have a couple of Hawke scopes. They are nice scopes (the image quality of my Panorama EV is particularly outstanding and I love the 1/2-mil glass reticle and the very even illumination), but they are both AO scopes and exhibit the approximately circular arc reticle shift that I’ve described above. (Actually, it’s the objective image that shafts relative the the reticle, but the result is the same–error in the form of a POI / “zero” shift). I’d like to buy a Hawke “Sidewinder!” I tested a friend’s 10x fixed power Hawke Sidewinder with my Zero-Point and the side parallax adjuster induced shift was small and only in elevation. I could live with it! 🙂


        • Cal
          I had a 30 mm tube Hawke sidewinder scope on my first Monsoon I had. It was a very good scope and a higher power scope at that.

          But the Hawke scopes I have now are the Varmint 2.5 -10 power 1/2 mildot scopes with the side adjust parralax.

          I shoot a little different with my scopes than most people do and its basically because of the distances I shoot at. Which is mostly around 20 to 60 yards. I zero at 50 yards and focus my parralax for 50 yards.

          I don’t move my sidewheel anymore for range finding. It stays at 50 yards and I use low power on the scope. 6 power to be exact.

          At those settings I can get a sharp focus at the distances I said. And my guns will use a 1/2 mildot of poi at those distances I said I shoot at.

          So I don’t worry about the parralax shift. My scopes stay put. About the only thing I will do if I have a windy day I will put in a few clicks of windage. And if the wind stops or the day is done then the clicks get put back to zeroed turret settings.

          I have 5 guns with that scope I mentioned and all 5 will shoot the same half mildot tolerance. In other words the guns will hold in a 1″ kill zone with my scope settings and power and pellet weight out put. And of course I have to do my part and shoot consistently.

          But I do seem to have better luck if I leave the magnification and parallax alone.

          And like I said I have a different way then most people. But I figure that is less variables to worry about. And I’m probably not explaining the best I could and it might not work for other people’s type of shooting they do.


          • >So I don’t worry about the parralax shift. My scopes stay put. About the only thing
            >I will do if I have a windy day I will put in a few clicks of windage.

            Well, I haven’t even mentioned the other sources of mechanical error and mis-calibration I’ve often found on scopes using my Zero-Point. The AO problem has just been the most prevalent source of significant error in my testing. If you can avoid adjusting stuff on a scope, you’re less likely to suffer from mechanical imperfections in it, I can testify to that!




      • Thanks, Reb!

        Well…I’ve thought about sharing some of my work in the form of a guest blog for quite some time. Originally, I thought I’d write a piece about gelatin-testing expanding pellets. I’ve been shooting many kinds of projectiles into home brew ballistic gelatin for years, but now it’s commonplace (from what I’ve seen on the web) so…yawn.

        Recently I thought I’d relate my latest method for bedding scope rings to correct for barrel droop or align the optic axis of a scope to a rife bore. I need to bed a new airgun scope to a mount soon so I’ll at least take some photos to use in a guest blog eventually, but maybe I should first write a blog elaborating on the parallax adjuster error problem that I’ve reported here. I could suggest methods to evaluate one’s own scope too and how to reasonably constrain their scope usage practices to mitigate the problem. The Zero-Point is no longer available, due to part vendor supply problems and possibly patent ownership issues, from what I’ve heard from Leupold personnel, but I have another evaluation method to suggest. I dunno–what do readers and and B.B. want me to work-on first? I’m trying to fix-up my family’s old house and get it on the market to complete a family move to a state a few hundred miles away, and I’m also trying to ramp-up some new business activities so I can’t promise anyone any adherence to a “copy deadline,” but I’ll do my best to get any sought-after information to everyone ASAP.

        -Cal





      • Glad to be of service! There’s really quite a bit to talk about with this scope parallax adjuster-induced error thing. At first I was quite surprised that, in all the scope tests I’ve read in the past, I’ve not encountered it. I really felt vindicated when Vortex tech support confirmed my discovery and was interested in it. Like other scope manufacturers, I’m sure, Vortex has some sharp people who know about scopes! To some extent I understand how people have unknowingly lived with the problem and not isolated it as a source of POI error, but I still find it to be surprising. On the other hand, most people just haven’t had the means or inclination to look for the error either and most scope tests aren’t designed to detect it.

        In talking to some of the high-end scope manufacturers at SHOT and also tech support people on the phone or via email, a few manufacturers do test their scopes (side parallax models at least) to provide what I’d call undetectable levels of error, but I don’t think such a manufacturing test criteria is common and, from what I’ve witnessed, it’s also not achievable at viable cost in the manufacturing of an AO (front adjust) scope. Though perhaps mechanically more complex, the “rank and pinion” side adjust mechanism seems to be less prone to these errors than the forward adjuster and moving objective lens.


        • Cal
          I think a guest blog is great like I said before.

          I was thinking BB could do a weekend blog and have a open blog about scopes. No particulars of were to start. But more like different things people have ran into or don’t understand about how a scope can work. Or different little tricks they came up with to make it better for them.

          Then there is the thing about scope dope and why its used. Then what ways mildots can be used. And what a mildot stands for. Then the different ways to range things with mildots and why is a certain power used for mildot referencing.

          There is just a lot of things to cover with that little tube we pick up called a scope.

          Maybe it would be cool if people wrote why questions and somebody out there should have answer. If a person puts a scope on a gun why are they deciding on a scope verses other types of sights.

          See what I mean the questions could just go on and on. Like why use click adjustment verses hold over and under and how to now how many clicks equal so much poi movement at 50 yards verses a 100 yards that most scopes are called out at. A scope that has 1/4″ of movement at a 100 yards will it have the same 1/4″ of movement at 50 yards.

          I’m kind of like you the list of questions could go on and on. Maybe that way BB can get the open scope blog going with some thoughts and what he has seen and just let the ball roll of whatever discussion comes to be about scopes. And other sights for that fact. It could be a in general sight blog.


        • I just bought my 1st AO scope a couple weeks ago but when it came time to mount it on my Rem. Airmaster I noticed it had picatinny or Weaver rings and wouldn’t tighten up on my 8mm dovetail so it’s been sent back now. and after this discussion I’ll have to do some soul searching to justify the expense of an even higher end scope. I was hitting my mark @80yds with 14 pumps in the gun with a Tasco 4×32 so it’s an accurate gun but I was wanting to leave it set for long range use but be able to use it in between also. Thus my rationale for the AO.
          I would also say that we don’t pay you so there is no deadline and you should write about whatever will hold your thought for long enough to finish.


  20. >“rank and pinion”
    Oops–I meant “rack and pinion.” I promise to spend more time proof reading any guest blog submissions, but I also know that Edith and B.B. will have a good romp in their review of my competencies, if I happen to slip-up just a little bit.



    • “Ranging methods using other than mil dots and zoom controls also comes to mind,” is a better way of putting what I meant to say.

      Then there’s my trick of putting a scope with a ballistic elevation turret dial for 62 gr. M855 5.56 ammo (like the kind Obama is now decreeing to be unlawful for us to keep and bear) on a 22 cal. air rifle. A typical 14.3 gr. CP or JSB pellet at ~620 fps works great with an M855 calibrated dial. Just zero the air rifle at 20 yards with the turret dial set to 200 yards. For air rifle use, simply divide the turret scale by 10 (200 yards for the 5.56 becomes 20 yards for the pellet, 250 becomes 25 yards, 400 yards becomes 40 yards, etc.). I discovered this useful trick with my ballistics software and I’ve verified it with a stock Benji 392 at the range (8 pumps and 620 fps) and a very low mounted scope. It works very well out to the 40/400 yard maximum of my dial. Beyond that, the pellet starts to “lose a little ground,” compared to the 5.56 round and the 10x rule begins to fail, but 40 yards is as far as I’d ever hunt with the 392 anyway.


      • I was plinking with my 392 on 10 pumps out to 60 yds with open sights on a telephone pole insulator( about 2″) this past summer and getting 5 for 5.but I agree with your 40yds for hunting. Those .22 pellets have quite a bit of drop after 40yds!



        • True. It averages approximately a click per yard, but it’s very quick with calibrated ballistic dials.

          The potential gotcha with dialing is mechanical hysteresis and slop in the controls, which I can also easily detect with my Zero-Point tool. If Leupold ever starts making Zero-Points again or if you’re lucky enough to find a used one for sale, I highly recommend the tool. I think every Leupold rep in the SHOT booth who saw me using my Zero-Point cautioned me to never lose it!

          I might have mentioned that I hardly ever use it for zeroing a rifle, because other methods work fine for me, but the Zero-Point is great for scope diagnostic work and evaluation. You can also use it to record the zero of a scope and then remove and replace the scope at at later date and get it back pretty darn close to the original zero. I have some improved methods for doing it that Leuopold does not cover in their instruction manual.



            • Gunfun1,

              Do you mean a picture of the ballistic dials/turrets or the Zero-Point? I’m sure you could make ballistic turret dials. Cloning the Zero-Point would be much more difficult, because it contains optics and it has a strong magnet to attach it to a muzzle.

              I’ll be lazy and not bother to take photos myself and I’ll try to defeat the blog spam filter (now that B.B. has told us the secret 😉 ) with some links.

              The ballistic turret has graduations in yards instead of MOA or 1/10th mils. The graduation spacing increases, naturally, with range and the marks don’t usually exactly line up with the “clicks” (you just pick the closest “click” to the graduation mark you want. Here the 400, 350, 300, and 250 marks would work with a low scope and the 14.3 gr. 620 fps 22 cal pellet at 40, 35, 30, and 25 yards, respectively. You’d zero at 20 yards on the 200 mark (not visible) and just ignore the graduations from 200 down to 100. (Ranges under 20 yards would require dialing up instead of down, but the error is small until under something close to 10 yards or so.)

              Please copy and paste the links and remove the spaces on each side of the slashes and the periods. Hopefully this post won’t get binned as spam then!

              forum . gon . com / attachment.php?attachmentid=408940&stc=1&d=1257387767

              A few scope manufacturers have scopes with ballistic dials for some popular cartridges. Leupold and Kentonindustries DOTCOM can make custom dials for your favorite load(s) for some of their scopes. Hmm–Kenton has some neat turrets, but pricey. You can buy a decent scope for the price of a Kenton E/V set!

              Some time ago I thought about developing Kenton’s business model myself, but never did it. Maybe there’s room to compete on price with them!

              Here’s the Zero-Point on a muzzle:

              fekete-moro . hu / field-target / czhajlas01.jpg

              Search on YouTube for “leupold zero-point.”


              • Cal
                I know what the ballistic turrets are.

                And the zero point is what I was talking about.

                And your links above didn’t work.

                Yea I’m going to search the zero point and see what its about right now.


                • Okay, Gunfun1.

                  Hopefully you found some good info. The Zero-Point instructions are not terribly comprehensive and I’ve never heard of anyone else using it as a test or diagnostic tool, but I think that’s its most unique and valuable application. Given that one can see a reticle move 1/4 MOA or less (especially if you pre-adjust the scope stadia to sit right up against a Zero-Point grid line with a sliver of light showing between them) a Zero-Point is far better for evaluating static (not under recoil) scope accuracy and performance than any live fire test, with all its uncontrollable variables (shooter, wind, ammo etc.).

                  One thing that people miss when using the Zero-Point for zeroing a scope (which is what Leupold designed it to do) is it can be used much like the dual reticle Sheperd scope (at least temporarily when not shooting). See shepherdscopes “dot kom,” if you are not familiar with Sheperd’s system. Like the dual 1st plus 2nd focal plane Shepherd reticles, you can view the Zero-Point “crosshair” and grid superimposed against a target simultaneously with the scope reticle. After you adjust your E/V dials to get your rifle on paper, by simply adjusting your scope crosshairs to match the position of the Zero-Point’s crosshairs, you remove the Zero-Point from the muzzle (important to remember this step or you might destroy the Zero-Point AND your barrel!) and take a shot or shoot a group. Then you place the the Zero-Point back on the muzzle and hold the Zero-Point crosshair on your previous target aimpoint as you look though your scope at the target. While holding the Zero-Point crosshair on your aimpoint, you adjust the scope’s E/V dials to position your scope crosshair on the center of your group. The scope is zeroed!

                  The Zero-Point image position is highly sensitive to off-bore tilt and it’s important that the barrel crown accommodates repeatable positioning of the Zero-Point using its strong magnet (at least “tilt-wise.”) The up/down and right/left Zero-Point position is nearly immaterial, but I think it’s best to try to center the the Zero-Point on the barrel so that any off-square tilt is more likely to be consistent between zeroing trials or re-zeroing after having recorded a rifle and scope zero combination on the Leupold supplied record forms.

                  Until you actually use the thing, this probably doesn’t make sense, but the Zero-Point “crosshair” and grid image from the Zero-Point to the scope is focused on the scope and does not move relative to the scope’s reticle when you shift the Zero-Point right and left or up and down. A Zero-Point change in tilt moves the image by moving the focal point to a new position and thus, for repeatable measurements, all measurements must be made with the same amount of tilt or any “off-squareness.” It’s much the same situation with a parallax-free red dot sight (or the See All sight). You may move your head up and down or right and left, but the reticle stays on target. However, if you tilt the sight (point the muzzle somewhere else), the reticle moves off-target. An outcome of this optical property is crowns that are not square (a bad thing anyway) will print off-bullseye when initially using the Zero-Point to just get on-paper (aligning the Zero-Point crosshair with the scope crosshair).

                  When using the Zero-Point as a test or diagnostic tool, measurements are usually conducted in one session / mounting of the Zero-Point on the muzzle, and minor tilt of the Zero-Point on the muzzle doesn’t matter as long as it doesn’t move while taking measurement. All you need is for the Zero-Point grid lines to be visible to find errors and the Zero-Point has to be cocked pretty badly before you can’t see the grid.

                  Hope this helps you to understand the device.

                  -Cal


              • Cal
                I checked it out.

                I do believe a laser bore sighter would do the same. But you would physically see the laser pointing on the target at different distances compared to what the scope see’s.

                Either way the big thing is be aware that scope verses barrel alignment can make problems with how well you shoot.

                And the zero point and look aser Bord sighter would show you those things.


                • Gunfun1, Read my new (lengthy) post and, hopefully, you’ll see how the Zero-Point is much more capable and versatile than a laser bore sighter–at least for work with magnification riflescopes as opposed to open sights, irons, or other 1x sighting systems. Though you can see the Zero-Point image at 1x and Leupold says you can use it to zero open sights, it’s pretty difficult!

                  You could use a laser boresighter for the Shepherd zeroing trick, if you could find one that retains its “aim” very precisely when removed and replaced. At the very least, the laser always has some off-axis tilt in the boresighter body, though you can mitigate this problem by always positioning the boresighter in the barrel in the same rotational position. Usually, the boresighter doesn’t seat or “chamber” quite the same each time. I’ve not found one that is repeatable to 1 MOA yet. Yeah–they are good enough to get you on paper, but a Zero-Point can get you back to within an MOA or better of where you had a gun and scope combination previously zeroed. A laser really doesn’t help at all for taking measurements or viewing scope mechanical errors. You need a measurement reference that’s stationary relative to the scope reticle to do that!

                  With my Zero-Point, I can even quickly tell you whether your scope clicks are calibrated in inches/100 yards, or MOA (4.7% greater than the former), or neither (you’d be surprised how many dials/clicks are poorly calibrated), regardless of how the dials are labeled. You’d also be surprised to learn how many dials are mislabeled “backwards” (MOA when the scope actually has inch/100 clicks or vice-versa).

                  Let me know if you have any questions.

                  -Cal


                  • Gunfun1, I just have to mention a few other examples of a few things that can be easily checked with a Zero-Point, in addition to what I’ve already mentioned:

                    1. E/W dial hysteresis/slop.
                    2. Mil-dot or ballistic reticle marking accuracy / adherence to the specified zoom power.
                    3. Image/reticle shifts with zoom control (or any other control) manipulation.

                    Again, it’s tough to evaluate these kinds of things very well using live fire or any other easily configurable and available test setup. That’s why I call my Zero-Point my “Optics Lab in a pocket!”


                    • Cal
                      A exsperianced shooter can basically check the things your talking about by shooting.

                      If you put targets at different distances like starting at 10 yards and placing a target every 10 yards out to 50 yards and always aim for the bullseye.

                      It will show you your left or right poi as well as your up down.

                      If you have gun that the scope is not set up right. When you shout at the targets you will see your poi move to the left more and more as your distance changes. Or to the right depending on how your scope is mounted.

                      And of course you will always see your up or down poi change at different distances.

                      And I don’t know if you seen where u talked about labeling those targets with the correct yards. Then go get those targets and place them on a table from left to right starting at 10 yards to 50 yards.

                      If you take a pen and draw a line to connect the dots you will see the trajectory of the pellet.

                      Now here is one step farther. Take those labeled targets starting with 10 yards and place the targets in order above each other. Not laying on top of each other but above each other vertically.

                      Now draw a line again connecting the dots. You will see the pellets flight path as if you were looking down at the pellet from standing above it.

                      That will show the true shooting result of your pellet verses the scopes sight path.

                      Do you see what I mean. We can use those instruments to set the scope up but the true results will be gathered from the shot taken.


                    • Its suppose to say I don’t know if you seen where I talked about labeling those targets for the yards they were shot at.

                      Then take and place them in the table in order as I said.

                      That will show you what the gun is shooting like compared to what the sight is seeing.

                      You can’t base the optics sight picture off of line of sight verses pellet trajectory.

                      The sight will never have the same line drawn as the actual trajectory line.


                • Gunfun1,

                  Yes–you can check all the things I’ve mentioned with live fire but, compared to using optical instrumentation even as simple as the Zero-Point, live fire is far less effective and you’re limited in how much you can check in a single test and the precision of any empirical resulst. Usually, it takes considerable effort to even investigate a single given potential source of scope mechanical error. Again, I can easily detect 1/4 MOA or less errors in several error modes. A very good bench shooter with a typical sporting rifle is usually limited to shooting no better than about 1-2 MOA groups. Sure, it’s possible to detect errors less than this by looking at groups and averages, but it takes a lot of ammo! Just think about how much shooting you’d have to do with a typical sporting rifle to detect random shifts of an E/W dials of only one click! Now try to detect E and W dial coupling effects, which can occur under unpredictable circumstances. For example, I learned that my Hawke Panorama EV windage control couples to the elevation control, BUT the coupling is “latent.” By that I mean that the shift in elevation does not occur until the next time the elevation control is adjusted and there is no error immediately upon adjusting the windage only. I further learned that the only way to avoid this latent coupling is to always terminate adjustments of the elevation dial in the down POI direction (tightening the erector spring) but strangely, the final motion of a windage adjustment must be in the right POI direction (loosening the spring). Unless the E/W controls are manipulated in this manner, latent error from a windage adjustment is about two clicks worth of elevation. Good luck finding that workaround with live fire, let alone discovering the problem at all!

                  The difficulties posed by live fire testing is the reason why I’ve read countless live fire based evaluations of riflescopes and never seen the AO problem I’ve described here. It’s not that shooters’ performance isn’t impacted by it either; they just don’t realize this source of error exists in the total “error budget” and they sometimes mitigate the size of the error with more extensive live fire testing and dope determinations, which sometimes can partially “absorb” the error. AO error can look just like wind too.

                  I think the next best approach for these investigation is not live fire. Rather, fix a rifle in a gun vise on a bench and use grid paper at a distance. The limiting factor is how well the rifle can be fixed in the vise and not disturbed during testing and, for some types of test like AO, how well can one perceive the measurement markings on a target that is out of focus. The Zero-Point remains much more readable throughout even a 5 or 10 yard to infinity parallax/focus adjustment than targets at any given range.

                  Finally, you can’t carry a bench, sighting rest, and range in your pocket! There is no way that I would have been able to evaluate the dozens of scopes I tested at SHOT with any off the shelf device other than the Zero-Point. Actually, I’d never have the time or ammo supply to fully characterize the performance and limitations of the more than a dozen scopes that I personally own and shoot.


                  • Cal
                    How do you determine the repeatability of the zero point?

                    What I mean by that is have you tested it by mounting and unmounting the zero point and see if it reproduces the same results.

                    Then take the same gun and shoot the gun and see if it reproduces what the zero point says.

                    I know what your trying to get at with the zero point. But I have to say this. We have optical comperators at work. I don’t know if you know what I’m talking about. But they are used to measure things by opticaly reflecting a image on a screen. And we have optical tool presetters that allow you to set center heights on cutting tools and locations of one tool to another in the same cutting head.

                    What I can say from using them to measure for years before we got our cmm also that we have had for a bunch of years. Is that anything to do with optics is hard to repeat results.

                    One person will focus different than another and get two different readings on the same measurement.

                    A scope can be put on a gun and set up and eliminate most of the alignment variables. But the scope will still have optical and mechanical variables.

                    But I gaurentee you that after you shoot the gun and put it on paper once the ballistics take affect you will have to go back through your set up to make corrections.

                    Bottom line point of aim verses point of impact will over ride any kind of set up tool you use.

                    Obviously the zero point and the laser bore sighter can’t be in the gun when shot.


                    • Gunfun1,

                      >How do you determine the repeatability of the zero point?
                      This is one of the features Leupold intended for the device. Leupold even provides paper figures of the Zero-Point reticle to record the “swap” data for each rifel. I have often moved scopes between several rifles. (Now I’m filling in the gaps with scopes). It’s easy to swap scopes. Yes–just mount the scope, adjust with the Zero-Point and shoot. Getting results with 1 MOA or better repeatability is easy. I’ve optimized the task a little, however. The most repeatable setting for the scopes crosshairs is a “light sliver” width separation from a Zero-Point “stadia” line. Before removing a scope from a gun, I mount the Zero-Point and dial the elevation and windage dials to position the scope reticle to this very discernible and repeatable position, while counting the clicks. I then record the position of cards I’ve printed from the Leupold figures and also record the number of clicks so I can restore the zero for that rifle very accurately later.

                      >We have optical comperators at work. I don’t know if you know what I’m talking about

                      In talking to the scope manufacturers, I’ve learned of many sophisticated test setups. In engineering grad school, I worked in a laser optics lab. My Masters Thesis was, “A Microcomputer Based Controller For A Liquid Crystal Lens.” As in machine work, usable and good consistent results are all about the setup! (Well–90% anyway. ;)) As an irrelevant anecdotal funny, we had a sign on the outside of the lab’s door, which leaded to a busy hallway and nearby lecture halls, “Do not look at laser with remaining good eye.” We had some real torches in the lab and the lock on the door was actually automated to engage whenever the lasers were running!

                      >One person will focus different than another and get two different readings on >the same measurement.

                      Progressive lens eyeglasses can cause this problem. I do not recommend them for precision shooting–even when staying in the distance vision correction area.

                      >A scope can be put on a gun and set up and eliminate most of the alignment >variables. But the scope will still have optical and mechanical variables.

                      One of the nice things about the Zero-Point is it’s very much a “back-end” check. You can check a scope zero after it’s mounted and immediately before shooting it.

                      >Bottom line point of aim verses point of impact will over ride any kind of set up >tool you use.

                      Including shooting the gun too, because it’s a “setup” and subject to many mechanical and atmospheric variables as well. For something you can carry around, it’s impossible to beat the “optics lab in a pocket,” unless you want to design something custom (but probably similar)!


                  • Cal
                    Here is what your showing with your zero point as you have said.

                    Your showing the discrepancy of what the scope will produce.

                    What the zero point is a pre set standard gauge if you will that shows the calibration of the scope and nothing more.


                    • >Your showing the discrepancy of what the scope will produce.

                      If by “discrepancy” you are referring to errors, i.e., undesirable, unintended, or non-ideal variations in the reticle position or size (magnification / reticle calibration errors), relative to the object image, then yes–the Zero-Point is good at this.

                      >What the zero point is a pre set standard gauge if you will that shows the >calibration of the scope and nothing more.

                      The Zero-Point scale is calibrated graduated in inches / 100 yards in both elevation and windage (not MOA). The graduations are spaced at 2″ intervals, but one can interpolate measurements to much better precision. However, the relatively coarse spacing is what motivated my technique to position scope stadia next to a Zero-Point graduation line with a small sliver of light between them. In moving an E/W dial 1/4 MOA or “1/4 inch” / one click, the movement is immidately visible. Actually 1/8 MOA dial clicks can be witnessed. This is a huge advantage over live fire testing, which necessarily becomes a probabilistic investigation. With the Zero-Point, if the reticle moves against the object (the Zero-Point grid) you see the movement immediately. Correlation becomes clear, and there’s no doubt as to cause and effect. The relationship is perfectly and quickly repeatable.

                      Although the Zero-Point is capable of detecting quite small errors using my techniques, it was not designed for empirical error analysis. If I were to design a tool for this purpose, it would probably be much like the Zero-Point, but with a high resolution reference grid. It would be useful to have higher resolution grids for higher power scopes too, where the high resolution could be discerned in measurements.



                    • Leupold intended the Zero-Point to be used as a tool for zeroing scopes and recording the zero position so it could be used to re-establish the same effective zero setting at a later date after removing and remounting the scope.

                      I mostly use the Zero-Point to quickly and easily detect and identify mechanical deficiencies in scopes (errors as small as something under a 1/4 MOA). It also enables me to quantify the errors to a precision of better than an MOA. With careful use, detection might be as low as 1/8 MOA. If the scope is mounted on a rifle with a normal steel muzzle crown, I don’t need any additional tools, ammo, range, or space larger than what’s required to hold the gun and myself. I don’t even need any light, if the Zero-Point’s batteries are good, because it is illuminated! 😉


                  • Cal
                    I actually have good luck unmounting and remounting scopes on the same gun and repeating poi verses poa.

                    The main thing is to mark the mount or ring location so the line of sight stays the same.

                    And one more question. Have you used the zero point to detect barrel droop?



                    • Good quality mounts provide 1/2 MOA repeatability, in my experience. What do you do when you move a scope between guns–count clicks back and forth? Regardless, the ZP provides a good check on the success of the operation before burning ammo.

                      Yes–barrel droop becomes quite obvious, because it causes the the ZP to “tilt” with the barrel and the ZP grid will be well off-center when the scope is zeroed. Furthermore, I used the ZP to help me compensate for barrel droop on my Diana 34. When zeroed, the scope erector spring was very loose (elevation adjustment near its maximum POI-up position) and the scope E/W settings were not stable. I recorded the zero position indicated on my ZP and bedded the scope to the rings using Acryglass epoxy (using release on the rings to enable scope removal). Part of the procedure I’ve developed is to set the E/W dials where you want them first (I like centered for windage and somewhere into the lower half of the elevation adjustment range for a tight erector spring.) Then I use dense foam blocks to temporarily shim the scope tube in the epoxied rings before the bedding epoxy sets-up to re-establish my recorded zero on the ZP. If you don’t have a ZP, you can do the entire process with the rifle immobilized on a gun vice and bore sight onto reference marks on a sheet of paper taped to a wall, or you could use a laser bore sighter. These alternative techniques are plenty accurate for this purpose but the ZP is so much more convenient and less prone to error.

                      It worked so well that I plan to write a guest blog using the commonly available sighting/alignment methods after I try it with release compound applied on the rings too. Thus, my next ring bedding job will result in removable custom-made ring inserts, similar to what Burris offers with their Pos-Aling rings. The other benefit of my bedding job or the Pos-Align rings is the scope is not stressed, as it is with geometrically imperfect rings or simple ring shims.


                    • I’ll also mention that, like Pos-Align inserts and angled rails/mounts, bedding rings obviates the need for heavy 30 mm tube scopes! If a scope is “pointed” in the optimum direction, rarely does one need the greater E/W adjustment range enabled by 30 mm tubes!

                      I hate how 3-9×40 or 4-12×40 hunting scopes that typically weighed under a pound a few years ago (and sometimes well under a pound) have been displaced by 30mm tube behemoths that weigh 1-1/2 pounds or more. The difference between a Leupold 1″ Ultralight 3-9×33 and the new 30 mm scopes is about a 100% increase in weight! Even the 1″ full-length Leapers scopes are running 1-1/2 lbs these days.



  21. Calinb
    Yes that is one drawback with those mounts and since the guns of mine that I have used them on have a flat top between the dovetails it has never presented itself as an issue.

    But I can see if the guns rail has the least bit of curvature to it that they most likely will not work and it would be possible to make a set with the under side radiused to clear such dovetail topped gun receivers a with little modifications.

    Glad you pointed that out since I have never had that issue it will help me and others when searching for options to mount scope as low as possible.

    BD


  22. Cal,

    When you do your piece of scope mount repeatability, don’t overlook one-hook mounts (Einhackmontage in German). They allow you to remove the scope is a second with a spring-loaded button, and the scope always returns to zero. I owned a rifle with a 1960s Nickel Supra scope mounted in them and it always returned to zero when remounted on the rifle. Your criteria of 1/2 MOA sounds entirely reasonable for that mount.

    Tom


  23. Cal
    So basically by bedding the scope your in a sense making a droop compensating mount.

    And you use your ZP to make sure the scope reticle is in the middle of the turret adjustments. Which is basically centering your reticle.

    And I’m pretty sure Buldawg posted a link above about me and him use a mirror to center the reticle and then shoot the gun to see how much droop there is with actual ballistics of the pellet involved.

    What I like to know is after you determined what angle to bed your scope with the ZP and you did that process. Have you shot your gun after that to see if the bedding came out correct for the ballistics involved?


  24. Tom, my first experience with mounting a scope was when I tried to mount a nikon prostaff 2-7×32 on a Savage Stevens 200 chambered in 30-06. I ran into exactly the same problem that your friend did. I was using a two piece rail, and the long action put the rings too far apart to be able to mount the scope. The tube was not long enough.

    I’ve since dropped that scope onto a .22 rifle, and I’ve been researching different options, from different scopes to different mounting options for the 30-06. I’d wanted a more powerful scope anyway, I’d just bought that one because it was on sale.

    I know I can use offset rings, or I can run a single piece rail. I don’t like the single piece rail idea, because it would make it harder to load the rifle. I’m having a hard time finding appropriate offset rings.

    I’m open to different scopes, but looking at scopes, no one seems to list the tube length. Everyone lists overall length, tube diameter, eye relief, parallax settings, etc,etc, and yet no one cares to list the tube length. If I can’t find the scope I want in person, if I have to buy online, what’s a guy supposed to do?

    I just got a marauder, and bought the CP 4-16×40 Adventure Class that PA recommends with it. While installing it on the marauder, it occurred to me that this scope would fit rather nicely onto my Savage. I haven’t pulled the gun out to compare yet, but I’m certain it would fit. I looked it up online, and it seems that that scope has a good history of holding up pretty well on heavy recoiling Center Fire rifles, even on rifles that recoil a lot more than a 30-06. A hundred bucks at PA, a little less if I want to buy from the godless heathen communists at China Mart or some online retailers (who shall not be named on the PA blog).

    So, what’s your experience with the CenterPoint scopes and Powder Burners? Do they really hold up well enough to take the heavy recoil? I had my heart set on the Nikon, but I can’t get info on the tube lengths of the other Nikons I was looking at. I was also looking at some of the Leapers scopes on PA, since I know you’ve recommended those pretty heavily in the past, but again, can’t find tube lengths, and I don’t want to drop the money on something, open it up, and find out it doesn’t fit. At least with the CP scope, if I buy it, and it doesn’t break, if I ever want to replace it later, the CP scope can find a home on some other air gun. I’m sure I’ll need one at some point or another.



    • Tim,

      I have no experience with the current line of Centerpoint scopes on firearms. When they were Leapers scopes I could say they could withstand any centerfire because Leapers builds all their scopes that way.

      But most scopes made for airguns are strong enough for firearms, because firearms recoil in only one direction.

      B.B.


  25. BB:

    Once again you’ve covered a great topic. My Remington 0.22 and Mini-14 both have open sights. I just got into Air Rifles within the last month. The Diana Model 34 I got through Pyramyd Air came with a scope combo. It has the special rail (if this is the appropriate term) to compensate for barrel droop. I watched a video on-line by Umarex about how to install the scope. What they didn’t cover was adjusting the scope. Thankfully there’s the internet and I figured out how to get the scope sighted by trial and error.

    I have a question for you related to scopes. Yesterday I ordered a Benjamin Model 392, along with the Crosman B272 intermounts, scope rings, and a Centerpoint Multi-tac scope through Pyramyd Air.

    My question for you is this. The scope rings come with a tape lining so that the rings don’t cause any damage to the scope. Do you recommend adding tape of some sort under the B272 intermounts to protect the gun barrel?I would like to protect the rifle from any damage caused by mounting a scope if possible. My goal is to make a short range hunting rifle (20 yards range) out of the 392 and use the Model 34 for target shooting.

    By the way, I’m having so much fun with shooting the air rifle. I have a 10 meter and 25 meter range in my backyard and can shoot whenever I feel like it. No more expensive ammo, picking up empty shells, and wearing ear plugs. Airguns are addicting. I have my eye on a PCP next! I even built a silent trap per your recommendations using duct seal to catch the pellets. I print the targets on my printer and cut out a hole in a $1.99 clipboard that slips into slots on the side of the catcher. I may even sell my 22 and mini-14.

    Your help is appreciated and you have no idea how much help you’ve provided me. Please take that as a compliment and keep the information flowing.

    Regards,


    • Spidey,

      I have never used tape between the mounts and the rifle. But yes, the mounts will make the paint flake off. So try it.

      A 392 is not well-suited to a scope because of how difficult the gun becomes when pumping it. It’s hard to grab the gun with the scope in the way.

      I will get to scope adjusting, but next I will cover installation, because several people have asked for it.

      B.B.


  26. Sorry Tom I click on to part 4 and did not find anything about the cometa fusion, I do like the looks of it and what I,ve read about it. I looked at the pneumatic guns you suggested,sorry a little to much for me thanks. The benjamin NP XL caught my eye good loking gun but the reviews about triger an scope wernt good so mabe a gas pistion would be good, I gess 50 yards will Do, Im thinking of about 450.00 tops plus a scope, kind of like the 1000 fps erea to and I like the mil dot sopes. Would like to jump up to 22 cal but if you think 177 is better for what im looking for I could go for it. Ok hope to hear from you soon about some good choices for me to pick from. thanks Rich.



  27. Mr. B.B.
    Got my scope remounted; thank you for that lesson, focused for 10 yards, that was a challenge and dialed in.
    Scope is rotated 45* now and windage
    My first 3 shots you’d be proud of, the next 7 slowly drifted high and right but all stayed with in a 1 inch group


Leave a Reply