Aligning a scope with the axis of the rifle bore

by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • Texas Airgun Show
  • The question
  • The bad news
  • Details
  • The barrel
  • Is the scope base parallel to the axis of the bore?
  • What about side-to-side?
  • Scope mounts
  • The answer
  • Greater precision?
  • However…
  • Close enough
  • What is meant by tweaking?
  • Never perfect
  • Summary

Texas Airgun Show

The 2019 Texas Airgun Show will be held on Saturday, June 22. Here is the website with information. This year they will offer FREE TABLES for people bringing a few airguns to the show! In the tent outside the entrance to the hall there will be several tables that are available to people who bring several of their guns but don’t have tables. These are the guys who normally walk the show holding onto airguns they want to sell and trade. You can now put those guns on these tables for free. There will be lots of table sharing going on, and you need to bring everything you need, because these tables are bare. This has never been done at an airgun show before and the promoters are hoping it will help those carrying their guns around to lighten the load.

Now on to today’s report.

The question

I have a Godfather of Airguns webpage, and sometimes people who read this blog ask me questions there because I guess they can’t figure out how to post them here. Today’s question comes up a lot and is worth a discussion. Here is the question.

“I have a question about the axial symmetry of scope mounts.

“Recently I bought an HW50S and I was looking for a scope mount. I decided to buy a BKL 263 two-piece mount because someone told me that this mount is perfectly centered to the axis of the airgun rail, and will not give me a horizontal error at different differences. Unfortunately the BKL was moving on my rail because of the lack of a stop pin.

“Then I decided to buy a good one-piece mount with a stop pin. But before that I checked my other Chinese one-piece mount. I mounted the BKL and that mount on the same rail and then I put a small BB at the bottom of each mount ring. I noticed that the BB on Chinese mount was displaced, relative to the BKL’s BB. Then I turned around the Chinese mount and did the same test. The BB was then displaced to the opposite side, so it means that the mount is not aligned with the axis of the rail. Actually it was near 2 mm of displacement. If the mount is for 9-11 mm rail it’s probably good for only a 9 mm rail.

“So here is my question. Will the Sportsmatch mount be axial to the rail, because I’m afraid it won’t? What should I do? Is that really important to have axial mounts on your airgun? Should I use a file and extend the not moving jaw of the mount to make it more axial?

“I was searching for your posts about that issue but I didn’t find any. If there is one, please send me how is that called or link to that post.

“I will be grateful for any reply. Thanks in advance for your time.

Best regards,
Matt”

What a question! Matt knows what many airgunners have discovered — scopes don’t look at exactly the same place that the bores of their rifles do. As you shoot close or far away, the pellet will move from left to right or vice-versa. I have written about this several times in the past but today I’m addressing it again. Matt, I never used the term axial, so that may be why you didn’t get any hits.

The bad news

Matt, the bad news is that no rifle on this planet does what you ask. I will get into the reasons for this in a moment, but don’t take it too hard. You asked if this is that important and the answer is no, it’s not. You can work around it and get what you want, despite it being virtually impossible to align a scope optical axis with the bore of a rifle.

Details

Here are most of the many reasons why scopes and rifle bores are never precisely aligned.

The barrel

We will start with the barrel. It is virtually impossible to drill a hole and rifle a barrel so that the bore is parallel to the outside of the barrel. But no matter because it’s not important. However, there are some anal benchrest shooters who think that it is important and they have their barrels machined outside to be parallel with the bore. This costs a lot of money (hundreds of dollars) and does absolutely nothing for accuracy. Know why? Because the place where the barrel joins the action of the gun determines where the bore “looks,” not the outside of the barrel. The center of the bore can be offset a quarter-inch from the center of the barrel and make zero difference in where the gun shoots.

Now, the place where the barrel is joined to the action does matter. That is what determines where the bore “looks,” relative to the action. So, time invested in getting that right is time well spent. But there is a fly in the ointment of today’s question. What kind of air rifle is Matt trying to scope? A Weihrauch 50 — HW 50. That’s a breakbarrel rifle, and we know that every time that rifle is cocked the barrel (and therefore the bore) moves, relative to the action of the gun.

breakbarrel
When a breakbarrel rifle is cocked, the axis of the bore and scope diverge.

However, this movement doesn’t matter as long as the barrel returns to the same place every time. And it does. So we can ignore the fact that the bore moves. Let’s move on to the gun.

Is the scope base parallel to the axis of the bore?

The answer to this question is no — most of the time the scope base (11mm dovetail grooves cut into the spring tube in the case of the HW50) is not parallel to the axis of the bore. I can illustrate this with a term we all know — barrel droop. Those who shoot breakbarrel air rifles know that most of their barrels point downward, away from the axis of their scopes. It’s the reason that droop-compensating scope mounts are so popular today.

drooping barrel
This rifle has a droop that’s extremely large, but it illustrates the point I’m making.

What about side-to-side?

I have only talked about the relationship of the scope and bore up and down. What about side-to-side? That can be off, as well, though it’s not commonly as big a problem. But some airguns have scope bases that are attached to the top of the spring tube, and those bases can be attached incorrectly, so that side-to-side becomes a problem. The fix for this is not the same as for up and down, because the trajectory of the pellet doesn’t come into play. In short, on a side-to-side problem gravity isn’t an issue. But it still needs to be corrected.

Scope mounts

Now that we understand the problems the gun presents, we still must consider the scope mounts. If the holes through the rings aren’t aligned with the ring bases everything else can be good and we still won’t get the scope and barrel to look in the same direction. The solution here is to use quality rings. And two-piece rings give you options for alignment refinement because you can turn them around or swap them on the rifle (front and rear). You can even swap them and turn them around individually, which gives an even greater range of adjustability. Matt mentioned doing this, so he understands the finer details of scope mounting. But now I want to stop talking about hypotheticals and get down to the answer.

The answer

Matt — let’s go back to those BKL 263 scope rings you say were slipping on your HW50. I have never heard of any BKL rings that are properly installed moving on any spring rifle, let alone one that is as smooth as the HW50. Something must be wrong with your installation. This is the very ring I would have recommended for the HW50 because of its precision. Are the rings really moving, or are you just concerned that they might? Because they won’t. Unless the rings are improperly installed or damaged in some way, they will hold onto the scope base of an HW50 so tight that any scope can be mounted securely.

Greater precision?

If you want the absolute last word in precision scope rings take a look at the UTG P.O.I. rings. I showed them in detail in the report titled Optics test. I doubt there are rings on the market that are machined more precisely than these.

However…

But here comes the real answer. Chasing specs like this to align a scope with a bore is a futile drill. Several years ago you read a lot about people finding the optical center of their scopes. There were even different techniques for doing it being widely discussed. You don’t read much about it these days because most shooters have discovered that it doesn’t make any difference. I remember 20 years ago when world-class field target competitor, Ray Apelles, told me that he had abandoned finding the optical center of his scopes. Instead, he just kept mounting and remounting his scopes and testing them after each tweak — by shooting them at different distances on the range and noting any shift in impact, side-to-side.

Ray told me that after he had optically centered a scope, none of his rifles would then shoot that scope correctly without some tweaking — FOR ALL THE REASONS MENTIONED AT THE BEGINNING OF THIS REPORT. It turns out that trying to fix the problem with specifications is a waste of time and money, because in the end all rifles have to be tweaked before their scopes and barrels can be correctly aligned.

Close enough

Hunters get away with not doing this because the error rate (the amount the scope or bore is off the target) is usually very small. A bird doesn’t care if your pellet hits him a quarter-inch from the point of aim. A field target, on the other hand, can lock up and not fall if the miss is that great. You lose points. So those folks who really have to hit exactly where they aim find it worth their time to do the work of tweaking their scopes and mounts — at least the winners do.

What is meant by tweaking?

To tweak a scope or mount, you use all the tricks in the book — shims, adjustable scope mounts, two-piece rings that can be swapped, front and rear, and also turned around. Matt mentioned that his Chinese scope rings were off by 2 millimeters. Ray Apelles had mounts that varied by as little as the thickness of the vertical crosshair, depending on the way they were turned. That’s how a scope is tweaked.

And don’t forget to install a level on your rifle. That way you shoot every time with the crosshairs and bore in the same attitude. Three degrees off at 45 meters will drop your pellet by half an inch if your gun shoots at 850 f.p.s.

Never perfect

And — get ready for it — even with all that you do it never works out perfectly! Hans Apelles, Ray’s father, told me they could get their rifles hitting where their scopes indicated to within half a pellet diameter at 50 meters, but they had to account for that final bit with holdoff. That’s correct — men who have placed in the top ten in world competitions and click-adjust their scopes for every shot would also hold off by the tiniest margin, depending on the range and the target.

Summary

So, Matt, you can go one of two ways, but not both. You can either chase after rings that are perfectly aligned with the bore of your rifle when they are installed on the scope base of that rifle — which I said can never happen — or you can spend the time it takes to modify and fine-tune (tweak) your scope’s alignment until you have gotten it as close as possible. You may even need to try many different sets of rings until you find the set that works the best. Scope mounting like this doesn’t take minutes, it takes weeks. But it’s the only way to get the job done right.

66 thoughts on “Aligning a scope with the axis of the rifle bore

  1. B.B.

    I bet Matt did not tighten the mounts dovetail screws enough. Without a torque spec his comments are worthless.
    If the bore and the dovetail are parallel but not aligned you can shim your dovetail mount. I’ve heard its been done, lol.
    How heavy a scope is he mounting? Yes the SportsMatch adjustable rings will cure all misalignment issues. But you will drive yourself to drink setting it up…

    -Y


  2. BB—-Thats why I use Burris Signature rings with offset inserts. Please look at their website and try the set that you have. Throw away your shims and stop turning your rings around. Use the off set inserts to tweak your scope. —–Ed




  3. B.B.,

    Thank you for the nice reminder of scoping correctly. On the RW I have the fully adjustable Sportsmatch rings and found them useful for initial set up.

    Just shooting and (knowing) what the hold offs are at different distances works too. I like when you said it can take weeks. Shooting, note taking, tweaking and then repeating. Most of all, verify results on multiple days/occasions. Even then, I find that if I check my zero at say 40 yards before every session,…. I may need a 1-2 clicks on E and or W for that day. I can adjust one day and then go right back to the previous setting the next session. Often times, no fine adjustment is required.

    Good Day to you and to all,……….. Chris


    • Chris,

      I see you have become a big fan of the fully adjustable Sportsmatch rings. They are most definitely the cat’s meow with PCPs. Many are scared by the price, but once you use them there is no going back. I have not tried them on an uber magnum sproinger, but I suspect they will work fine there also.



        • Yogi,

          Thanks for that tidbit. With reflection that makes sense. These mounts are capable of fine adjustments and the recoils, vibrations and twistings of an uber magnum sproinger can play hardball with just about any sight system. I would hate to spend this kind of money on a nice set of rings and turn around and ruin them.


          • RR,

            My take on that is,.. are they recommended for firearms? A large caliber powder burner is going to put one heck of a whooping on a set of rings/mounts. I do not think the rings really care which direction the are getting a whooping from.

            Perhaps B.B. or Shootski may have an opinion on the Sportsmatch rings and powder burners? Or,…. anyone of our other fine members that shoot powder. When researching at the time,… there were several variations/brands that have quite a bit of adjustment.

            Chris


  4. And this is a perfect report for something I mentioned in the past.

    Place a piece of paper at say 10, 20, 30, 40 and 50 yards. Put one dot on the center of that paper. And label each target what distance it is at. Then aim with the center of the reticle at that dot. Don’t use no hold off when you shoot. Then see what the paper says. You can even take 5 shots at each paper if you want.

    Now here’s the kicker take the same gun and same pellets and mount a red dot sight and do the same test shots on new paper. Then go one more step farther. Do the same test with open sights.

    If anyone does the experiments let me know what you see. And this may be interesting to some. If you take them target papers and place them on a table in order by the distance it was at. Remember when I said label each target for distance. We’ll now you can actually see the trajectory of the pellet by looking at the lined up papers. Take a pencil and go from target to target connecting them together.

    What your going to find is even with the open sights or the red dot sight their will be a side to side shift of pellet impact as well as up and down. No pellet flys in a true arch of only a up or down hill path. There is side to side movement as well in the flight of the pellet. And I’m not talking from the wind. I’m talking even with no wind.

    So if someone does the experiment you might find it’s not the scope after all. All your doing with a scope by shimming or whatever method is used is overcome the pellets flight path. All I can say right now is try the experiment.


    • GF1,

      Some of Ted’s old You Tube videos showed pellets spiraling through the air. I guess finding the right pellet for accuracy includes one that spirals much tighter. The better balanced the projectile, the less obvious the spiraling will be.



      • RR
        Maybe I should explain something about that test I’m talking about.

        Let’s say we sight our scope or a red dot or open sights at 30 yards.

        And what happens is that on the targets below 30 yards the pellet hits a 1/4 inch to the left. And again out at 40 yards a 1/4 inch to the left. But out at 50 yards it’s almost a 1/2 inch to the left.

        What I would do with that gun would be to zero the scope about a 3/16 of a inch more to the right.

        That would then make the pellet hit closer to scope zero at closer distances than 30 yards and likewise at distances past 30 yards. So that way what is happening is your keeping your pellet hitting closer to your zero aim point.

        And then of course there is then the normal hold over or under that you would use at closer or longer distances.

        Doing what I say you can really dail in your scope, red dot or open sight.

        Again shoot at some paper at the distances I mentioned and see how it works. That’s how I set up my guns.


        • Oh and forgot something else.

          The faster the velocity is the less you will see of that left right movement of the pellet plus less of a trajectory arch with the up down pellet impact.

          But keep in mind that is in a given distance and if you have a gun that groups good at the higher velocity.

          The way the pellet flys makes all the difference. That’s why field target shooters like a pellet that has a flatter trajectory. And the smart shooters know that the pellet hits at different axis from the place that the sight was zeroed. Again how the gun is sighted is what brings the pellet in closer to aim point.


        • GF1,

          I understand your testing method and approve of such. I do pretty much the same thing.

          That is the beauty of the Sportsmatch rings. If it is hitting to the right at 50 yards and to the left at 100 yards, you can adjust the rings to move the scope more in line with the trajectory and greatly reduce the variances.



          • RR,

            It the POI was to the right at 50 yards, wouldn’t it be off to the right at 100 yards, only farther to the right? For example, POI is 1″ right at 50 yards and 2″ right at 100 yards. I’m confused.


            • Geo
              You didn’t read what I said.

              It all depends on what distance you have your sight zeroed at.

              And it depends on if your gun has left or right hand rifling.

              And the pellet could be off to the left at one hundred yards instead of the right. Like I said the pellet doesn’t fly in only a up and down trajectory. It also curves to the left or right after it leaves the barrel.

              That’s why I said try the test targets like I said. At 30 yards I’m dead on. In closer or out farther I’m shooting to the left of where I zeroed the gun.

              Seriously try the target test I mentioned. You might be surprised what you see.


              • GF1,

                Yes, I did read your comment and I do agree with what you are saying. If the pellet corkscrews then I can understand the POI being left at one distance and right at another. There’s always something new to learn. I rarely shoot at pests at more than 35 yards so I am probably not aware of the left / right pellet shift. I do know that at 35 yards and less I do not have to compensate for shift though. Maybe if I try shooting 50 to 100 yards it may show up.

                I haven’t actually shot at paper out to 50 yards because the Urban is so effective at pesting that I haven’t seen a need to do that. It would be interesting to test it though.

                Geo


                • Geo
                  Do the test I mentioned. And one more note. I should of mentioned to write on the target what your gun is zeroed at.

                  And yes cork screw would make the pellet shift left right or up and down depending on what axis the pellets at when it impacts.

                  But I think what your missing is when the pellet leaves the barrel it will shoot in a curve with a downward arch also.

                  In otherwards say you have the barrel pointed upwords at a 30° angle. The pellet will fly like a rainbow shape but also curve to the right or left.

                  So if your sighted at a certain distance that could make your pellet hit left of your zeroed in distance then move to the right past your zero in distance then end back on the left side of your zeroed in distance.

                  If you shoot a slow flying heavy pellet what I’m talking about really shows up. The faster the pellet goes and the lighter the pellet is the less of that effect you see. And that’s what you want.

                  Then it’s just a matter of zeroing your scope to the left or right to keep your pellet impact as close to center aim point as possible.

                  So say I got a nice flat shooting pellet out of one of my very accurate guns. And say it will hold a 1/4 inch up down and left right from 10-50 yards. But I’m hitting more to one side than the other. All I do is put a couple clicks in one way or the other to get that pellet impact as close to zero aim point as possible.

                  So in my test that was 10 yards to 50 yards. Now that I got the pellet averaging out hitting in my kill zone from 10-50 yards. That makes it a lot harder to miss that sparrow at those distances.

                  So stop thinking only spiraling pellets. Think of the pellet flying in a curved rainbow path.


            • Geo791,

              Besides the fact that the pellet is spinning through the air which can introduce a spiral effect to the trajectory, the question arises about how well everything is aligned.

              Is the barrel bore in line with the scope mount grooves? That would be a rarity.

              Are the rings perfectly aligned with each other? The better quality rings come closer to that.

              How well are all of the lenses aligned in the scope body? A slight angling of any of the lenses will throw things off.

              How well is the optical view of the scope aligned with the bore? This is where issues really show up. Aligning the bore and the optical view to be parallel eliminates many of the errors, but what happens when the bore and view are parallel on the horizontal and vertical plane, but the view and bore are offset to one side or the other? Are the grooves parallel to the bore, but offset to one side or the other? As you adjust for zero you have a converging at that range. At a shorter range you will group to one side and at a longer range you will group to the other. WWII fighters had their wing mounted machine guns adjusted for converging fire at a certain range. At shorter or longer ranges the grouping would be more open.

              So how do you fix it? With adjustable mounts you can not only change the angle of the view versus bore, you can move the plane vertically and horizontally. By doing such you can reduce or eliminate this error.



      • RR,

        I watched one of Ted’s recent videos demonstrating this phenomenon. The slow motion video showed some of the pellets spiraling. It happened on one or two times out of ten. The pellets that didn’t spiral hit the target and the few that did spiral, missed. His camera did an excellent job of showing the spiraling pellets. I cannot remember if he had a theory as to the reason for the spiraling pellets though.


        • Geo,

          Here is an interactive link that shows spiraling. There is other good interactive demos if you go to their home page link at top. A very good site, especially for newbies (not that you are).

          I did not see a demo that explained left at 25 and right at 75 (for example). I do believe it is like GF1 said,…… at your sight in zero distance,… you will be on. Less and you will to one side and more you will be to the other side. Spiraling,… if occurring,… could make one believe that they may have a barrel to scope alignment issue.

          http://www.arld1.com/nutation.html

          Chris


          • Chris,

            Thanks for the link. Very interesting things on that site and I bookmarked it for future reference. I printed out the target with 63 1″x1/2″x1/4″ bullseyes and scanned it into my targets folder.

            I wonder how one would differentiate between the scope being out of alignment to the barrel verses the natural curve that the pellets makes, as explained by GF1.

            Geo


            • Geo,

              To be honest,… I am not sure. If a barrel/scope issue,… I would think that you would see a (steady) progression in one direction (then the other) when diverting from zero + or -.

              If spiraling is an issue, it needs to consistent. That way you click compensate. Same for barrel /scope alignment issues. Needless to say,.. you have to actually shoot/document and stick with the same pellet.

              Not sure, but some of the comments indicated that some pellets spiraled, while others did not. If a different weight/type/brand,… I could see that. If the same weight/type/brand,…. then that would be an indicator that the pellets have some variance within the same tin.

              Yes,.. that is great site. It is my go to for someone new. Plus,… so much of it is interactive where you can actually change things. It is truly one of the best learning tools that I have ever seen.

              Chris

              By the way, the neighbor has an adult ground hog and a baby that frequent his yard. A new challenge, as they are extremely challenging. I may take a sit and wait approach.



                • GF1,

                  Got it. Setting up targets all perfectly in line and all level, plus,… the gun in line with all of that would be a bit of an hassle,…I would think. Do-able and worthy of results, but a hassle none the less. Targets at every 5-10 yards is more to my liking.

                  Chris

                  Plus,… even punching through single layers of paper (multiple single times) might also have an effect on the trajectory VS going thorough just 1 layer, 1 time. After all,… we are talking abut something doing 800 fps-ish VS something doing 2000-3000 fps.


                  • Chris
                    No it’s not like that totally.

                    If you put the targets out at the 10 yard increments. And where you can see the next farther target your fine.

                    Remember the next target in line is a new target. If your to the left say 30° on your next target distance that pellet is still following it’s same trajectory.

                    Your just shooting at a different location in your yard.

                    Think about it. Do field target shooters only use one lane when they shoot at the next target that’s at a different distance than their last target. No

                    And use 10 yard increments. By going every 5 yards your throwing in more variables and you will find you won’t see much poi change at 5 yard differences.

                    And a level yard would be great too. But again to much.

                    You will find if you do the target test I’m talking about you will see how a particular gun changes at different distances and locations in the yard.

                    Some guns change alot. Some don’t.

                    Do the test and keep it simple and see what happens. And do one gun and then set up targets for another. Bet ya they will be different. Then your next job is to get both guns shooting as close to zero aim point as possible. When you can get both guns doing that then you know what I’m talking about.

                    It’s not easy at first. Don’t chase your tail. Just let the gun perform and see what the paper says.


            • Geo
              The only thing your doing when you shim or adjust the adjustable scope rings is move the scope in the direction you want the pellet to hit. Basically what that does is keeps your scope true front to back which should keep your scope sharp farther out to the edge of the sight picture.

              That’s why optical centering use to be important to some shooters that use all of their scope picture. In otherwards someone that shoots at a hundred yards and they might be using 5 or 6 mildots of hold over for how they have their scope zeroed for a certain distance. It keeps the scope seeing a sharp picture all the way out to the outer diameter of the scope picture. And yes the right way to do that would be to zero out at that distance if that’s the only way you use that gun. We are talking shooting at different distances. So it does complicate things a bit more to make the gun shoot how you want.

              Try looking through your scope the next time and point the gun up but still keeping your eye on the target. The farther you get away from center the more you will see the target getting unfocused from your scope not being in alignment for how your looking through it.

              That’s what shimming does for you. It keeps the scope line of sight true front to back to where your pellet hits. So doing it that way is one step better than clicking the scope like I was saying. But both ways work. And also the people that do use scope clicks instead if holdover and under and windage hold already have their scope optically centers and the scope shimmed to keep it true. They then put up and down and left and right clicks instead of holding off the gun.

              The trick that I think everyone is missing is how you can dail in the pellet as to where it hits within a certain kill zone. That’s what is important. That’s what makes it easier to hit the target at different distances.

              And remember a spiraling pellet is not a good flying pellet. That’s another variable that causes problems. I want to talk about the good flying pellet from a known good grouping gun. That’s what we are trying to do here. Get a good shooting gun to shoot better.


            • Geo
              Why does it matter if the barrel is not in line to the scope.

              That only matters if you want the optics of the lens to be seen at it’s best when you look through the scope. Again that’s reticle centering..

              Get that done then make your pellet hit as close to center reticle as you can.

              Why do we care what position the barrel is to the scope if we have a sharp scope picture and the pellet hits as close as possible to where we aim.

              Of course it would be nice if the scope and barrel was close in alignment. Then we wouldn’t have to go crazy shimming or adjusting rings just to get sight picture focus out to the edges.

              We can cheat a little here and nobody would no the better when you come out and hit every target they aim at. They will just think your a good shot. But little do they know what you did to make that happen. That’s what we are talking about here. Make your gun easier to shoot. It takes a little time. But once you see the results you will be doing it on your next gun.


    • Great minds do think alike. Now that I have access to a long shooting ranges at my club, I’ve started re-zeroing my scopes for 20 through 50 yards (and noting the elevation settings). I’d discovered that the rifles will shoot off the X ring (left or right)
      at 50 yards even though they were zero’d at 20 yards. However, once zero’d at 50, they were still in the X ring at 20 although slightly (within 1/2 inch) left or right (depending on pellet and rifle) from point of aim. Close enough for vermin work!

      Fred formerly of the DPRoNJ now happily in GA


    • GunFun1,

      I saw a video of pellet flight that showed the flight path as a spiral. There are a couple such videos on YouTube. The host on one of the videos found that his airgun barrel needed a pellet in the 5.50 to 5.51 mm. One out of three larger pellets would spiral. He achieved greater accuracy in his rifle after sorting pellets to select those that were optimal for his rifle.

      So many variables, so little time! 😀

      Dan


      • Dan
        I can shoot long long distances with my air guns where I live.

        When I shoot my .25 caliber out at a hundred yards and more and the sun is right I can see the pellet. I can’t really see good enough to see the spiral but definitely can see the trajectory of the pellet. It’s real fun to watch on a windy day.

        But I have seen at closer distances on other guns the pellet spiral. But that was because the pellet was clipping the baffles in a shrouded gun.

        But yep like you said variables. How to eliminate them is the problem. Some you can if you work at it. Others like wind and such you have no choice other than not shoot when it’s windy. Like that’s going to happen. I actually like shooting when it’s windy sometimes. Good practice.


  5. B.B,

    Thank you so much for the whole report. I’m really satisfied with your answers, really!

    The BKL that I owe are probably defective. When I wanted to slip them to the rail the were very loose. I heard that they are sometimes needs to be extended before installing. My are opposite. So to get them hold the rail you need much pressure from screws. After the first installation I put a piece of tape on a dovetail to see if they really moves and they did (I cleaned the rails with alcohol before installing). So I wanted to give more pressure to the screws and then one of the thread in the mount was stripped (I replace that screw with the stronger screw with the nut but it doesn’t solve the problem. I will probably get a new one BKL.

    Matt



      • B.B

        For the future, should I write me questions here or by e-mail?

        And my last concern. Is it ok to put a piece of electric tape onto the rings where they contact the scope tube?

        Matt


  6. BB
    The last time we discussed scope rings in the blog it was noted that it is very important to keep the top ring cap with the original base. Not only that, make sure the cap is not reversed when you install it. I checked a few rings and found they were off quite a bit in bore alignment simply by installing the top backwards.
    Match them all up prior to installing them. Some were so bad they could probably dent the scope tube when tightened up. You can feel a ridge inside the bore where they match up if its backward and if reversing it does not help, you probably do not have the original cap installed that belongs there.

    I can’t remember the name of the new rings we were talking about before but I believe they were precision machined with alignment pins installed and perhaps springs ? Any one recall ? Heck I hate senior moments.


  7. Three degrees off at 45 meters will drop your pellet by half an inch if your gun shoots at 850 f.p.s.

    BB
    Could you please break down your above statement with a little bit of specifics sir?



  8. Hi B.B.,
    I’ve been waiting for a report on scopes so I could ask you a couple of questions I have been keeping in my back pocket (hopefully, others have these same questions):
    1) When I do a search for “best fixed power scope for air rifles,” I do not get much in response. The most results I get are on the PyramydAir site; I get 17 of them here: https://www.pyramydair.com/search-results-ext?Ntt=fixed+power+scope&sid=1375A617A415&N=0&Ntk=primary&q=fixed+power+scope&cx=002970863286801882398:jlcminxfwdw&cof=FORID:11;NB:1&saSearch. Are there other scopes out there, perhaps higher end, that PyramydAir has decided are not worth it to carry due to the lower demand for fixed power scopes?
    2) Of the fixed power scopes I see, I know you have spoken highly in the past of the UTG Bugbuster scopes; I have seen the 4X and the 6X; in the reviews, I have seen mention of the reticle seeming “fat” on the 4X model; is the 6X model better in this respect, as in, at the higher power does it appear to cover less of the target?
    Thank you in advance for your consideration of these questions.
    Take care & God bless,
    dave


    • Dave,

      The reason you find so few fixed-power scopes for airguns is because so few are being bought. The demand is for inexpensive variable-power scopes with AO

      Yes, the reticle on the 4X Bug Buster used to be fat. It’s probably still thicker than many would like, but maybe not as fat as it was 10 years ago. The 6X scope, by virtue of having 50 percent greater power, has a reticle that covers less.

      Looking into my crystal ball, would an etched-glass reticle in a fixed-power Bugbuster be of interest?

      B.B.


      • B.B.,

        I was looking for just that thing; a small Bug Buster sized scope with a good reticle and either 4 or 6 power. A parralax adjustmend would be good on the 6 power but not needed on the 4 power if it was set for the best focus between 10 and 35 yards. That is where much of the backyard plinking and pesting seems to be.

        For me the illuminated reticle is not desirable, keep the cost down. I have a:

        https://www.pyramydair.com/s/a/Winchester_4x32_AO_Rifle_Scope_Rings/1227

        It is the best I have found, but has a thick reticle. I think it was Geo that recommended this scope. An etched glass reticle would take care of that.

        It seems that the typical buyer wants all the knobs and lights they can get on whatever they buy, scopes included. I don’t know how well a simple quality 4 power scope will sell but I will definately buy one.

        Don


        • “Looking into my crystal ball, would an etched-glass reticle in a fixed-power Bugbuster be of interest?”

          Thanks for the replies B.B. And to your question, I would say, “Yes!”

          “For me the illuminated reticle is not desirable, keep the cost down.”

          And Don, I am with you on that as well; keep things SIMPLER, with less to go wrong; let the quality go up, and the bells and whistles go down. =>


        • Don,

          If the Geo you are thinking of that recommended the Winchester 4×32 scope, it wasn’t me. I have a Hawke Sport 3-9×40 AO scope on my Diana 34P and a UTG 3-12×44 SWAT scope on my Gamo Urban, both have etched glass reticles and illumination. Both are fine scopes. I do use the illumination when shooting in my basement range. In low light situations the illumination works very well. Also, when sighting on a black starling, the red illumination works great too. I don’t normally even change the magnification on my scopes. I leave it pretty much at 10x where I know the mil-dots are right for hold under or holdover.

          Here’s a blog from 2007 that BB wrote on scope mounts. I’m sure things have improved since then. I have BKL offset mounts on my Urban. Unlike most scope mounts, the BKL mounts self center. I had to use the spreader screws to open them enough to slide on to the dovetail on the Urban. 11mm dovetail rails can vary from 9.5mm (.374″) to 11mm (.433″) and even larger. This is a pretty big range for a scope mount to accommodate and fit correctly.
          https://www.pyramydair.com/blog/2007/03/11mm-scope-dovetails-why-do-they-interchange-with-38/



            • Don, my rememberer is not very good either. Tonight my wife called in a pizza takeout. She told me it would only be 15 minutes. The pizza hut is about four miles from us so I was getting around to go pick it up. My wife said to me “don’t forget your billfold”. Well, I got half way there and suddenly realized I had forgotten my wallet. Had to turn around and go back home to get it.


      • BB,

        Etched is the “bee’s knees”,…. as another way of saying it. I would imagine that etched will be the only thing found in a few years on anything that is even half good quality.

        Chris


  9. Chris—Many decades Bauch & Lomb had a series of scopes with fixed reticles ( Balvar). They were popular with my club mates. However, after 5-10 years of use, the glass picked up particles that were very annoying. The matt black paint inside the scope tube was the source of these particles, and they stuck to the glass that the reticle was etched on. I would hesitate to buy a scope with etched reticles, unless I was sure that the paint would not flake off. I know that this is possible, because I have 5 Shepherd scopes with etched reticles. I have had them for almost 30 years, and the reticles are still free of particles. However, these scopes were expensive. Low and medium priced scopes may not be up to Shepherd standards. 3 # of these scopes went to Africa with me on 2 of my safaris. They were well tested. ——–Ed


    • Ed,

      Like car rust,…. things have improved. Interesting real life perspective though. Powder coat is about the only thing left for non car production. It is some tuff stuff. Anything spray on,.. I would be suspect of until knowing the clean, prep. specifics. Good luck on anyone finding that out.

      And,.. your comment points to that you get what you pay for. Well,… most of the time anyways. I like the fine and precise lines of the etched.

      Thank you,…… Chris


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