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Air Guns How to mount a scope: Part 1

How to mount a scope: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

This report covers:

  • The olden days
  • What needs to be done
  • Eliminate cant
  • The tale
  • More information
  • The scope must be angled down
  • Adjusting the scope too far right is also bad
  • Not experts
  • Position the eyepiece
  • Adjustable scope mounts
  • Is it enough?
  • Points to remember
  • Summary

The olden days

When I started shooting in the 1950s, scopes were not that common, especially on airguns. I was as intrigued by them as anyone, believing that they increased the accuracy of whatever they were mounted on. 

Well, they don’t. What they do is make it easier to shoot accurately with a given airgun or firearm. But they can only do it if they are mounted on the gun correctly and then sighted in properly. This series is dedicated to addressing all that is inherent in both mounting a scope correctly and then sighting it in properly.

What needs to be done

To properly mount a scope there are several things to consider. Here is a list.

  • Secure mounting
  • Proper eye relief
  • Angle the scope so the elevation doesn’t have to rise above halfway
  • Align the optical axis with the boreline
  • Eliminate cant

I have written more than 30 reports on scope mounting since March 3, 2005, when this blog started. I will draw on them as I go, but I’m also going to break some new ground. Not that scope mounting has changed, but B.B. Pelletier has changed over the years. He has gained experience!

Eliminate cant

Canting is a subject all by itself. I won’t deal with it today.

The tale

To tell this story I will begin with a tale that happened to me a week ago. A friend from church told me the scope on his Gamo breakbarrel had broken — that the crosshairs are now sitting cockeyed

cockeyed reticle
When the scope is still mounted tight on the air rifle but the reticle looks like this, the scope is broken.

Stock up on Air Gun Ammo

More information

In our second conversation he told me something more. He said his scope wouldn’t hold its zero. Right away I knew what the problem was. The scope’s elevation was adjusted too high and the erector tube return spring had relaxed, allowing the erector tube to bounce around as the rifle recoiled, and also vibrated, as I discussed yesterday.

erector tube
The erector tube inside the main scope tube contains the crosshairs. When the scope is adjusted this tube is what moves. The crosshairs remain in a constant position and only move because the entire tube moves. The erector tube is also where the magnifying lenses are.

Where the reticle assembly is located in the tube makes a difference. If it is at the front of the tube it is called a first focal plane scope and because the erector tube is what magnifies the image, the reticle enlarges as the power is increased. If its located at the rear of the tube the reticle remains the same size regardless of magnification and that is called a second focal plane scope.

The scope must be angled down

What most rifle owners don’t know is the axis of their barrel points down. It is not aligned with their receivers, despite what they believe. This is so common on the AR-15 that special scope mounts with a down angle have been created. If you search the internet you’ll find AR-15 owners complaining that their expensive scopes and mounts won’t hold zero and they are getting lots of advice to change the scope and mounts. The problem is — the advice they are getting is all wrong. They have a barrel droop issue and have adjusted their scope’s elevation too high.

I have been at the range when a guy with an AR was sighting in. He had his elevation adjusted up past the 3/4 mark, which he had to, to get on target at 100 yards. The scope will never hold a zero when adjusted that high. He was shooting 4-inch groups before I had him adjust the scope down 60 clicks. Then his groups shrank to around 1.5 inches. Of course they were too low, but that can be fixed. Let’s get back to airguns.

When I examined the mount of my friend’s Gamo Whisper rifle I found a deep scratch along the top of the aluminum scope base on the rifle. Whoever mounted the scope, and I am guessing it was done at the factory, did not put the scope stop pin inside the hole in the scope base. Constant recoil and vibration caused the steel stop pin to slide along the top of the scope base and dig a deep furrow.

scope base
Whoever mounted the scope didn’t put the stop pin into the hole in the base. They just tightened it down as tight as it would go with the subsequent sliding along the base from recoil over the years.

scope stop pin
This scope stop pin on the bottom of the one-piece scope mount of the Gamo Whisper should have been placed in the scope base hole, not tightened against the top of the base.

Adjusting the scope too far right is also bad

Adjusting the scope’s elevation too high is bad and the same holds for adjusting the scope too far to the right. The erector tube spring relaxes and the tube starts moving under recoil. But too far to the right is rare because it’s easy to see, where the droop is harder to detect.

Not experts

This is where buyers sometimes miss the boat. They think that if the company that made the rifle also mounts the scope it has to be done right. They don’t appreciate what goes on in those companies — that someone with little or no training is given the task of installing scopes on rifles. They certainly don’t then shoot each rifle to test their work. Some will mount them right and others won’t.

Now, if a retailer like Pyramyd AIR mounts a scope they do it right because it’s their name on the line. I used to scope rifles for customers when I worked at AirForce Airguns. I did take the time to zero each of them, which is how I came up with the 10-foot sight-in process that I wrote about.  And I gave the 5-shot group I shot to the customer, so they knew how well their rifle could do. But that kind of service is the exception rather than the rule. What we see here — the mis-mounted scope mount and no regard for barrel droop is more common.

Position the eyepiece

Another complaint my friend from church had was the eyepiece of his scope was positioned too far forward. All he saw was a small image instead of the full image the scope is supposed to show. So I also took care of that when I mounted his new scope. 

Adjustable scope mounts

The best solution to a rifle that droops is to mount the scope on an adjustable mount. It’s expensive but my vote goes to the Sportsmatch scope mount that can be adjusted while the scope is on the rifle. But a guy spending $275 on a breakbarrel bundle isn’t going to pop for $150 more just for a scope mount. So my less expensive solution is to shim the scope under the rear ring.

shimmed scope
There is the shim I put under the scope on the rear ring. It’s a cut-up credit card.

shimmed scope angle
And this is what that one shim did. The scope base is level. The scope is slanted on a downward angle that’s visible, relative to the scope base.

When you tighten the ring caps don’t tighten them too tight or the scope tube will bend. When it’s shimmed it’s no longer cradled in the ring that’s designed for it. The new angle will help keep it from moving in the rings during recoil, so the caps don’t have to be as tight.

Is it enough?

Is what I did enough? We won’t know until the rifle is sighted in and tested. That job falls to its owner, though I stand ready to help if he needs anything further.

Points to remember

  • Most rifles shoot down and need their scopes mounted to compensate for it.
  • Scope rings need to be mounted to the scope base correctly if they are to do their job.
  • If a scope’s elevation is adjusted too high the scope may not hold a zero. Same if it’s adjusted too far to the right.
  • Don’t over-tighten the scope caps when the scope is shimmed.


That’s it for this report. If I’ve left something out or not explained it well enough, let me know.

author avatar
Tom Gaylord (B.B. Pelletier)
Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.

155 thoughts on “How to mount a scope: Part 1”

      • B.B.,

        This is an excellent report. You are absolutely right to remember readers just getting into airgunning.

        Additionally, there might be more than a few folks out there like me. I am an experienced airgunner, but I have little experience with scopes as I mostly use iron sights and shoot at short distances. But as I get older, my vision worsens, so I expect I will have to invest in more scopes and mounts.

        Cant is something I look forward to learning more about. I know what it is, but curing it is a subject I am clueless about.

        Again, an excellent report.


    • Taemyks: It can take a while to learn the techniques that BB is teaching. I learned a LOT from reading his blogs and applying it to my arsenal. I have learned to assume that I do need a drooper mount, usually a single piece. He taught me the importance of lightly tightening the side clamps to the dove tail with enough slop to feel the seating of the stop pin in the dove tail hole. Then I tighten all the mount screws.

      I have concurrently learned that, despite usually assuming the need for a drooper mount, I often STILL have to shim the scope and to adjust the mount caps VERY carefully with the MINIMUM of force possible to prevent creasing the thin scope chassis.

      I also learned, on my break barrels that a short torpedo type level is a wonderful thing in league with the door frame of my ballistic closet in the basement range. I carefully align the rifle while it sits in my Case Guard Predator rifle/pistol stand so that the level, balanced on the flat of the breech block is, in fact, level meaning the chassis of the rifle or pistol also is. I then work to twist the scope in the mounts by increments until the vertical reticle is in alignment with the plumb door frame of the closet. This requires multiple rechecks of the torpedo level and the scope and frame alignment. I then begin tightening the cap screws starting with the front mount point since the angular displacement is less than the rear. I tighten and check, tighten and check. Things will move sometimes. This process can not be hurried and can be frustrating, to say the least.

      When I am reasonably sure the scope is fast held enough that it is unlikely to move, I do the tighten and recheck routine for the rear mount. When I am done, the reticle is theoretically plumb to the rifle’s vertical centerline and plumb to the door frame.

      Then the 10 foot shooting into a fresh target page starts with initial attention to alignment of POA and POI. If I am not on the bull, it usually means cutting a shim and doing the above plumb adjust and tighten interval and shoot again. I don’t adjust the turrets until I am well into the roundel, and preferably in the 7 or 8 ring.

      It took quite a while to understand the basic teaching that BB reiterates – DON’T use the turrets for gross adjustment. Now, that seems simple and logical enough, but it took a while for that to sink in. One doesn’t usually learn this nor is it talked about much beyond BB’s blog.

      Don’t be too hard with the new shooter. I’ve had a most experienced fire arm shooter express no end of frustration with one of his vintage and lovingly cared for M-1 Garands. He scoped it but the scope had an off-set parallel to but not on the vertical plane of the barrel. I had him explain what was going on and I pointed out that he had a serious line-of-sight vs. line of ballistic travel problem, they were in parallel and not at any point in the same plane horizontally nor vertically. The light went on in Mike’s head and a smile spread across his face! It wasn’t his marksmanship nor anything wrong with the hardware – they just weren’t mated properly for the task but off set so that a very limited congruence between POA and POI could be attained in terms of distance.

      Some things require more than intellectual knowledge. They require a certain number of frustrating experiences from which to learn.

      • LFranke
        Good comments. One point in your paragraph about the 10′ range; your POI should be the distance below the POA (bull) that you measure between the center of your scope and the center of your bore. The pellet is still rising at this point and will be closer to the bull at 25′.
        from Algona

        • That is correct. I don’t really worry about the scope axis/barrel axis for my purposes with my 10′ shots. I am more concerned not to chew up the ballistic closet wood work or punching holes in the hollow closet door. I just want to make sure that I am reasonably certain that when I back up to 10 M that shooting in the middle of the Champion Pellet Trap the pellets will be within its mouth.

          I do the serious adjustments from that point forward off the Case Guard table and rifle/pistol rest.

          One coincidental thing is that for shooting at vermin discretely from inside three sides of my house (via an open window and raised screen), the 10 M distance from the basement range approximates my property lines. I won’t shoot out the front windows of the house to the street because that could be a very bad thing. So, my target guns are just luckily set for the occasional marauder who wants to munch on my ornamentals or few tomato plants.

          BTW, I never shoot two critters: skunks, because they “explode”; and possums because those shy creatures are nature’s garbage men and tick eaters. Other furry annoyances, however, take their chances….


  1. I have tried various techniques to align the scopes vertical axis with the gun. Levels and plumbbobs etc. Now I set the scopes vehicle cross hair to bisect the center of the breech. Move your eye from side to side and make sure the crosshair moves the same distance to each side of the center of the breech. Also move your eye front to back till you just see the full view through the scope not more not less then the crosshair should cross the center of the breech.

    The only way I know to do better is to make micro adjustments to the scope rotation while shooting groups at all the ranges you are going to shoot. You better already know what pellet you are going to shoot. So shoot group shots at 10 yard increments collect data on the scope rotation to find the best compass point. Make etches on the scope and the base so the rotation can be duplicated. Don’t use the top of the ring as that changes each time they are loosened. I tried this one time and quit before I finished. It just took the fun out of shooting.

    If you are careful and spend a little time getting the scope aligned with the vetticle other variables will be more important. Most mounts do not align the scope over the center of the barrel anyway, especially the dovetail mounts that have variable widths and dimensions.

    Remember as B.B. says if you are shooting at the same distance every shot it doesn’t matter anyway. So sight in at your most common shooting distance.


  2. There is something I noticed when I shoot my guns rapid fire with a scope or dot sight. I shoot right handed and I tend to cant the gun over to the left when I hold it. The guns I’m talking about don’t have a adjustable butt stock. They are fixed stocks.

    And the thing I want to bring up also is I still hit what I’m shooting at. Basically the cant is happening because of the way the gun fits my shoulder.

    Saying that what I do with my fixed stock guns is I shoulder the gun then get the cross hairs on my scope as level as I can.

    Doing it that way I have good luck bench resting and free hand shooting also. Done it that way for years.

    Wanted to add that with adjustable butt stock guns I hold the gun level and then rotate the butt stock to fit my shoulder. Then I get the cross hair as level as I can to my hold again.

    The main thing to get accuracy is to be able to repeat your hold. The way I see it is a given gun will need a different scope set up for each different person that holds that gun to be able to shoot it accurately.

    • GF1,

      Cant is something I have tried to avoid since I was a wee child. You say you are canting the gun but leveling the cross hairs. Based on the various distances you shoot with the accuracy you get you are eliminating cant significantly. You can not cant the gun and get your accuracy at different distances. I think your cant is minimal. Or consistant and sighted at your extreme distance. That way the cant effect will be minimal.

      A good experiment would be to sight in with a normal hold at 10 yds then shoot at 50 and 100 yds and see how the windage of the poi changes.

      Cant is one factor that is pure geometry and balistics. If your groups windage centroid changes with distance that is because of geometry; unless there are environmental changes (wind etc).

      This is a good discussion.


      • Don
        I done went through all that testing with a canted gun and scope.

        I put targets out at different distances and aimed at one dot on the center of each paper. I kept the gun rotated the same amount also. What I noticed is the farther the distance I shot the more the projectile was off the aim point.

        But what I also noticed is that when I shot from let’s say 20 to 50 yards with my gun zeroed at 35 yards I had to cant the gun a fair amount to get the pellet to hit off more than a inch to aim point.

        So what I’m saying is if I was slightly canted and shot at those distances I just mentioned I could still maintain a 1 inch kill zone.

        Now like when I shoot out at 80 to 150 yards then yes I better have a gun canted the least amount as possible and repeat my sight in hold as well.

        And another thing about cant. Try a particular gun with lower scope mounts and do the cant test I mentioned above. Then put tall scope mounts on the same gun and do the test with the gun canted the same amount and see what happens.

        And remember this. As much as you try to repeat your hold with your gun you probably will not always repeat your same hold that you sighted the gun in with.

        You will always have some degree of cant if a person is holding the gun. Right or wrong?

        What it boils down to is how much cant can you have for the type of shooting your doing. And you can plum bob all you want and use other techniques. You will always have cant to some degree.

        • Gunfun1,

          Because of all your experience shooting over the years, I think you probably have two kinds of adjustments in your shooting routine: conscious adjustments for things such as cant (and which you describe above) but also subtle, unconscious adjustments you have unknowingly developed and use over time. They have become so automatic and so small, you don’t even notice you are doing them to compensate for various factors. Some of these unconscious adjustments are probably unique to you, and they work for you every time.


          • Michael
            For sure. I remember teaching my daughters to shoot.

            One bigger thing was picking up on that they would cant the gun as the trigger was being pulled. It’s hard to learn to pull that trigger straight back and keep pulling till the shot goes off.

            Right now I have the trigger set so well on my Gauntlet that my oldest daughter commented to me saying… dad I wish this trigger was on the guns we was learning on.

            It is set in a sense like a set trigger. You feel a slight resistance almost like something is rubbing. Then the trigger stops like a trigger set with a long first stage. At that point you can take your finger off the trigger and it stays in that position. And when you set your finger back on it is ready. You just squeeze with a very slight pressure and the trigger is like it’s on a stop. It doesnt even seem to move and the shot is off. Its so predictable it isn’t funny.

            And yep kind of like a 6 sense in a way when I shoot. I don’t even realize the different pressures I use on the gun with my trigger hand thumb and fore hand fingers and thumb. I have to pay attention actually to realize how much I’m actually putting into my hold automatically.

            Its hard thing to explain to a new shooter when your teaching them.

        • GF1,

          One thing we haven’t discussed is the large offset of the pellet and sight line at the longer ranges. This makes the cant effect even larger. Say you have 2 ft of pellet drop at 100 yards. Think of your sight line as fixed and rotate your gun around the sight line your poi makes a large arc. Now take a gun with 1 inch of drop at 100 yards. You will have a small arc. Both sighted in at 100 yards. So it is not just scope height that affects the cant effect.


          • Don
            I done that too at different distances with targets. I tryed to keep the guns as level as I could.

            At sight in distance I was dead on and if I shot in closer the pellet would be off to the left of aim point. Or if I shot out farther it was off to right of aim point.

            So yes that’s a factor too.

            But how about this. What does the twist of the rifling do to the pellets flight? Does the pellet trajectory also curve to one direction in windage as well as a arch like a rainbow in in elevation.

            Again maybe balistics is affecting that too?

            • If there is a significant crosswind the spin should have the curveball effect. I have not read or heard about it but have wondered. It should move toward the direction where the spin is against the wind, higher velocity lower pressure. It may be insignificant I don’t know. Probably if the wind is strong enough to create a significant force you won’t have a chance with a pellet gun anyway with windage.

        • Don: I agree with your conclusion in the main, there will always be some degree of cant when shooting. What I do, for my air guns is seek to have the pieces as aligned on the vertical axis as possible using my level, door frame and nit-picking set up. I want my pieces as mechanically aligned as I can get them.

          After the gun is made as mechanically fine as possible, then there is only one variable for the cant, ME! Part of marksmanship is to identify one’s technique errors and address them while shooting. That is both the interesting challenge of the shooting sports as well as its source of frustration.

          • LFranke,

            I agree, well said. Practice and interest has made me a better shooter.

            Now consider music, I am a lost cause. I cant pun intended play a radio. I love music just have no ability, I have tried. I think natural ability is crucial to becoming proficient and required to become tops. Fishing and shooting I have always done well. Not so much with hunting and shotguns. Part of that is I am right handed and left eye dominant.

            Back to the gun, I give the scope setup a bit of anal effort and no longer look back. To night I spent some time with a Red Ryder shooting cans from 10 yards to 25 yards. I shoot with three holds, one handed, two handed with the butt off my chest and third with the butt against the center of my chest. The gun is too small for a typical hold. I start with the gun against my chest and work to the one hand hold. Even though the one hand hold is the most wobbly I do well with it. It is like willing the bb to the can. I think I shoot the Red Ryder as much as any gun I have. It is so relaxing. Even Kate my wife gets into it. She could be better than me but is not that interested. She does beat me in clay pigeons most of the time.

            • Don,

              An ex-wife learned to play piano by ear as a kid. I had a nice acoustic guitar, but like you, could never quite get it. At any rate, she had never picked a guitar up and within 1 hour she had about dozen chords correctly figured out,.. by ear. I had to check my chord book to believe it! Like you said,.. some people just have a natural talent.


              • Chris U,

                I had a cousin that had polio when she was 2 or 3 years old she was quite a bit older than me. She could not speak. She remembered two short phrases but that was it; they were spoken randomly.

                If you turned on the radio and gave her an instrument it would not be long before she was playing along with the songs. She played the piano and organ in my uncle’s church. She played very well.


              • Chris USA: Yes, as a pastor, and retired counselor and social worker, I have observed that there are different kinds of “intelligence.” I can’t dance worth anything, but am amazed at the precision and replication of routines of those who do. Similarly, when I was in high school band I could play my tenor sax, but realized I was but a musical technician NOT a musician; that is also a different form of intelligence. Brains are amazing things, and the differentials in the ways in which they work are even more amazing.

                Somethings can be acquired and one can develop some expertise, but there is a quantitative difference in the way some people are able to access and work within a given area of knowledge or discipline and the ordinary folks. Call it genius or expertise, but some brains just “have it and get it” where others have to work at it. That doesn’t negate practice for the gifted, they just start in a far different place than others.

                Let us be thankful for these gifts of genius among us. These gifts drive us forward as humans and as civilization bringing advances in all kinds of arts and sciences. It is more than just inspiration or flashes of insight, it is intelligence.


          • LFranke
            And that’s exactly why I was bring up these different questions today.

            I had in my mind that people were doing alot more things with their shooting than we ever discuss here on the blog.

  3. B.B.,

    How do you determine the proper position of the scope for another person? I mean the eyepiece was mounted too far forward for him so I assume you moved it backward but will it still be forward enough for him to avoid injury to his eyebrow?


    PS: This Report Covers:
    – Adjusting the scope too far right is also badNot experts

    – Adjusting the scope too far right is also bad
    – Not experts

  4. BB
    I mentioned this before but this is a good a place to repeat it.
    Check the bore alignment within the rings. The top cap may not align with the base half if it is turned around or switched with the other cap.
    I don’t know how all the rings are made or packaged, bored out first and then cut in half and assembled willy nilly?

    I have a lot of scope rings and while searching for a set that works best for a given rifle I did not pay too much attention to which cap belonged to which base ( same size, same company ) until I found one that the screws did not line up to tighten when the scope was installed. I rotated it 180 degrees and it fit fine.
    Surprise the heck out of me so I removed the scope and inspected the alignment inside and sure enough it was out of alignment so much I could snag my finger nail on the ring top when snugged up. It was right on when I rotated it.
    It may just be a thing with cheep rings, or ones with four or more screws, but I use a lot of them with inexpensive airguns..
    I would also snug up the rings on the scope just enough to allow them to rotate and check how the rings line up with the rail on the airgun. They may line up better if one is rotated 180 degrees.
    Not really a big problem there they will usually straighten up when tightened down but then the stress is transferred to the relatively soft scope with the same results as a misaligned cap, or shims too tight a dent in the scope.
    Bob M

  5. BB,

    Looking for a gun with P/W scope rails is a big plus. Or,.. find an adapter the converts 11 mm to P/W.

    I just measured a credit card. It is .032″. Of course you have done it, but that seems a bit too thick, not to mention rather stiff. I use a cut piece of toothpaste tube. There is some foil in there but also some plastic on both sides. It is pliable and at the same time has some grip. The piece I have cut is .011″. I think?,… at one time that you recommended no more than 2 water bottle shims.

    The thicker the shim is, the more chance of bending the scope tube.

    Droop compensation mounts are good too, if you can find something that you like and will work. This is also the time to get a 11 mm to P/W mount if you can. I have used several with great success,…. at the same time,… they can raise the scope up pretty high,.. so use lower rings if you can do it. All of my objective bells have been 3/16″ or less off the action when done, regardless of mounts.

    If using a stop pin, set it to the rear of the hole.

    On eye relief, in most cases you can move your head forwards or back a bit,… so there is some forgiveness. The (next level) to that is finding your most relaxed position when shouldering the gun and (then) move the scope for best eye relief/best picture. Too shoot your best, you do not want to be contorting your head, neck or eyes in anyway. Finding that “natural fit” is critical. Here too, you may (want) high rings for better eye alignment, when low rings would work,.. but make you stress your neck/head more.

    Also, when mounting a scope, the loading port and using any magazine must be taken into account. The bottom bulge of the scope turret mound comes into play here.

    I think it was Geo that had to get an offset mount that stuck out (past the rear) of the existing rail that was on the gun,… to get the scope closer to the eye.

    Also, the advantage of longer scopes vs shorter scopes. There is a whole lot more tube fore and aft of the turrets that will make set up much less of a hassle.

    That is all this newbie has for ya’. 😉


      • Hank,

        If you think about it, those are basics. At the very least, you want to (be aware) of them, even if mounting a scope for the first time, in order to get best results. (or the best you can, with what you have)

        Before I forget, what about adjusting the ocular to get a clear reticle picture? Is that not “basic”?

        All done? The scope turret is blocking me from using my magazine. 🙁
        All done? I have to move my head up and down on the comb to get a good sight picture. 🙁
        All done? I have to move my head backwards or forwards to get a good sight picture, but I don’t have enough adjustment with my rings and scope. 🙁

        Remember the (close your eyes) grasp, shoulder (open your eyes) trick? What is my view? Do I need to move my head? Repeat several times. That will tell you a bunch on what direction to head.

        So far in Part 1, we have been made aware of droop and compensated for that. We know about scope slippage and know to use stop pins. The scope is now mounted tight to the rifle. Looking forwards to Part 2.


    • Chris,

      I do not know if Geo did such, but I did with my Webley/Hatsan Tomahawk when I mounted a Bug Buster on it. I used one of these which also allowed me to adjust for droop.


      Some did not like it, but I do.

      • RR,
        Yes, I did have to use BKL offset rings. The adapter you linked to might have been a good option in my case too. It certainly would have been cheaper. Live and learn. 😉

    • Chris,
      Yes, it was me that had to buy new offset mounts. I opted for the compact UTG 3-12×44 AO scope for my Gamo Urban. Standard rings did not allow enough movement to obtain good eye relief. There is little difference between the compact model and the standard model as far as weight and size, and if I had it to do over, I would buy the standard scope. The adapter rail mentioned by RidgeRunner might have been a good option too, and I could have used the Weaver rings the scope came with. But, I bought the BKL Offset rings at a cost of $49. They are very nice rings and, unlike most standard rings, they self center instead of pulling one side against the dovetail.
      Another lesson I learned early on is to make sure the scope has an AO (adjustable objective). My first airgun was a Crosman Nitro Venom which included a CenterPoint 3-9×32 non-AO scope. I had not yet learned about the need for an AO scope when used on an airgun. My required pesting range in 25 yards and the CP scope image was fuzzy at that range. I did manage to correct it somewhat by unscrewing the front ring and then adjusting the lens slightly. Another good lesson on selecting a scope for an airgun.
      Lots of good lessons for newbies here. 🙂
      First image is with the standard UTG rings. Second image is with the BKL Offset rings.

  6. BB,

    Nice report. Good timing for any newbies out there and a great refresher for us old geezers.

    This is pretty much how I go about it and have for as long as I can remember. This is how my Daddy taught me. I have never used any of those fancy level systems or gun mounts or plumb bobs or whatever to mount a scope and have placed my projectile in the space between the eye and the base of the ear of a groundhog many a time at hundreds of yards.

    I do like those adjustable mounts. Yes they are expensive, but if you really like shooting a particular air rifle (or powder burner) a lot they are worth the investment, even if you are shooting a “cheap” air rifle.

    You did not mention these and this is likely not the place for such, but there are the scopes with bubble levels in them. Years ago I bought one, but the optics were not that great and I sold it. In recent years I bought a UTG with a bubble level in it to try again. Excellent optics, but what I find is that you spend a lot of time watching that bubble AND trying to line up the reticle with your target. That is fine if you are shooting bench rest or field target, but that fuzzy tailed tree rat may not sit there while you fiddle with all that stuff.

    • RR
      That’s right with the fuzzy tails.

      That’s why I say you should shoulder your gun which will lock you in better on your shot. Then comes the part if your cross hair is level.

      There is no time to get the cant out on some shots. It all boils down to knowing your gun and repeating your hold.

      And yes I got many ground hog at 100 yards when I was a kid. Most of the time I was resting the gun between a Y in a branch on a tree. Shouldering was important that way also.

      • GF1,

        Learning the nuances of your airgun/firearm, how it shoulders, how it feels, how it recoils, etc. is so important. The eye is a wonderful creation and will help you to level the sights, whether they be a reticle, a peep or a V with a bead out front. As you get to know your airgun/firearm, it takes less and less time to take the shot and you become more accurate with that shot.

    • RR,

      I bought one of those bubble levels for my Impact because the scope is quite high (about 2 1/2 inches over the bore) and I was seeing cant errors at longer ranges.

      Took a bit of time but now that I am used to it I liked it enough to order another for the Royale which has a large objective lenses and needs a high mount. The levels I got are inexpensive ($13 Canadian) and are good value for the money.

      Find that I am subconsciously aware of the bubble and only “notice” it when it is out of position. Seems to work fine for me weather shooting from the bench or offhand.


      • Hank
        Right you only notice it when your out of position.

        I’m like that when I see the cross hair when I’m sighting. Once you shoot enough you pick up on the cant real quick when your off.

      • Hank,

        I bought one of those levels. I plan to put it on my Ruger 1022 squirl gun. I forgot to bring the 1022 down last time at the cabin and the fires are keeping me home. I guess I should try it on a pellet gun.


  7. BB, I had a new Gamo Whisper about 16-18 years ago. My brother ordered for me, and had it tuned by the late Bob Werner. I mounted a scope on it, and I did put that stop in in place, torqued the screws on the rings, used Loctite. The scope did not hold zero, and I found that shooting a few hundred pellets caused the pin to elongate the hole in the mounting rail as it moved back – it was a relatively thin and soft aluminum extrusion – a separate part screwed on the top of the receiver. My gun was an example of an overpowered springer.

    • JerryC
      My experience with scope slipping on a Gamo was about 5 yrs ago with the Bone Collector 1300 model with the gas ram piston. That gun was just plain snappy and I had a terrible time trying to get the scope mount from sliding clear off the gun. My pin stop hole also got very elongated. I finally succeeded in getting it tight with a tube version of Loctite and Very carefully tightening down the screws.
      At the end of all that, if shot decently and there was promise of inherent accuracy. However, I realized I thought the safety and trigger were both crappy and I didn’t’ care for the snappiness so I gave it to my nephew.
      I now keep mostly spring rather than gas ram airguns and don’t desire any more Magnums.
      from Algona

  8. BB,
    You mentioned above “What most rifle owners don’t know is the axis of their barrel points down. It is not aligned with their receivers, despite what they believe.”

    Why is this done by the rifle makers? I can say that I’ve not experienced barrel droop that was indicated by my scope being raised far above the optical center on anything other than my air rifles. So does that mean that not all gun makers do this? And once again, why do they put droop into the barrel?

    • Cloud-9,

      It’s not done intentionally. It just seems to work out that way. I supposed if a maker approached it from a Value Engineering standpoint they could rectify the situation, but I haven’t heard of any who have tried. The modular rifles that are coming into vogue may be a step in the right direction.


      It’s interesting that RAW has adopted the modular chassis systerm for their air rifles, too. Already well-known for accuracy, is RAW trying to leap even farther forward?


      • BB,
        As I think about this more, modular rifles or rifles with movable/removable barrels (ie. break barrel airgun, Ruger 10/22) may suffer more droop due to tolerance buildup from manufacturing or wear or thermal expansion than another rifle with a very rigid barrel (ie. underlever airgun or Remington 700). As an engineer and machinist in the past, the only explanation for me must be the critical tolerances for colinearity of the barrel to the receiver and the difficulty maintaining those for some designs or manufacturing processes.

        • Cloud 9,
          I agree with your analysis. When you think about it, in a break barrel airgun the alignment would be determined by the relationship of the dovetail machined in the breech to the surfaces at the end of the breech and barrel where they meet at closure. Being that those surfaces are only 1/2-3/4″, any out of squareness of these surfaces to the dovetail would be magnified many times at say 25 yards. They would only have to be off a .001″ or so to greatly affect the POI at extended ranges.
          On other types of air rifles where the barrel is mounted into the breech, there is only a couple of inches of engagement. Any out of parallelism of the bore machined into the breech to the dovetail would also have a magnified affect on the POI. The machined features will always have tolerances and there will always be some variability. It’s all about the geometry and it’s amazing that the parallelism of the dovetails to the centerline of the barrel bores is as close as it is.
          These are my thoughts coming from a machining and metrology background.

    • Droop will also look like ballistics when sighting also.

      Different velocities and weight of pellet will make a gun seem like the barrel has droop.

      Some gun barrels are obvious. But I would like to see someone measure droop on a barrel and show how they came up with that.

      Seeing is believing.

      • GF1,
        I agree seeing is believing. My observed experiences come from moving a scope and rings between the same model of different underlever spring rifles, shooting almost the same velocity (within 20fps), and shooting the same pellets. The result was that the new rifle required 2 rotations of the elevation turret to rezero the gun at 30 yds when that scope was previously zeroed at 30 yds on the other rifle. I didn’t measure the difference using any of the methods described herein today, so I only have POI differences as proof. I also couldn’t tell just by looking. I couldn’t shoot that way, so I used the Burris Signature PosAlign rings to alter the scope to barrel relative angle and get the scope back to optical center when zeroed at 30 yards. I chose not to bend the barrel on this one as I have seen done on some airguns.

    • Cloud 9, I think it is because it forces me to depress the verticle poi on my scope to compensate, some times all the way to the limit of adjustment. As the range of my shot increases, the POI lowers, I use the upper range of my mil dots to compensate for the perceived bullet drop. Plus, a bore can be out of alignment axially on the left to right too. I notice this when my gun is zeroed at close range, but the shot drifts left or right at longer range. When I adjust for the windage, and then re-zero at close range, it’s off the amount of the adjustment. So Like GF’s solution to use cant to compeste for this.

  9. I believe it is incorrect to say that barrels and receivers (at least on most, if not all, firearms) are not aligned. This seems to be common with break barrel air guns where the barrel’s bore axis and the bore axis of the spring housing (receiver) are not coplanar- ie, angled to one another. Thus, the barrel ‘droops’ in relation to the receiver. The AR15 family of guns depends on bore axis and bolt/carrier axis to be aligned in order to function properly. Many other guns require this alignment as well.

    I think the term ‘barrel droop‘ has been applied, secondarily, to the dimension that is measured between the bore axis and the line of sight through the mechanical center line of the scope. This is referred to as Line of Sight Above Bore Axis. This dimension is exaggerated in the straight line guns (ARs, Ljutic shotgun, etc.) and bullpups.

      • GF

        You can pretty well figure it.
        Center the scope. Roll preferred.
        Measure the center of the scope to the bore center. You will need this in a moment.
        Use chairgun or other to figure pellet drop to target. You will need this in a moment.
        Shoot a big target. See where you hit.
        You should hit about where the distance between the scope center distance and trajectory (added) figures out to be.
        Significant difference will be your droop, if there is any . Probably will be some.
        You will also see how much you will have to adjust the scope. Will you have enough adjustment range ???


        • TT
          That is with the sighting through the scope factored in.

          Probably one way would be to show the actual droop or rise or left right of the scope to the barrel would be to have a laser bore sighter on the guns barrel then a laser mounted true on the objective bell of the scope.

          Then aim the scope laser on a piece of paper and see were the bore laser points on the paper compared to were you point the scope laser. It would be like you described above without the ballistics of shooting the pellet.

          That way you would eliminate balistics of the pellet. Right?

          And of course you would have to figure out a way to check if the lasers were true to the scope and barrel.

            • TT
              I know.

              The only other way I know would be mount say a 18 inch long bar that is 1 inch diameter in the guns mounted scope rings.

              Then take a ruler or machinist scale and measure the distsnce between the bar and the barrel by the scope ring and out at the end of the 18 inch bar by the muzzle end of the barrel.

              That would tell for sure if the barrel to the scope center is off. Then you could measure the bar in the scope rings to the breech at the front and rear scope ring. That would tell you if your ring saddles were true to the breech.

              That would probably be the better way to find out if the barrel actually has droop or if ballistics is causing the effect of droop. What you think?

                • TT
                  That would be fairly easy. You could either use a caliper and check the bore to the barrel or find a precise gauge pin to go in the barrel bore at the muzzle end and measure. That would be the only spot that would matter on the barrel because that’s were the pellet exits the barrel.

                  Also the bar would probably need to be 24 inches long or more to make it from the scope rings to the end of the barrel. And I would use a lighter weight aluminum bar verses a heavy steel bar.

                  In the end it would for sure tell if it’s ballistics causing the droop or if its actual barrel droop.

                  That’s why I dont believe what I hear unless I see it.

              • GF1,

                I think that using a 36″ or 48″ steel yard stick (alum/ or steel) laid on edge in the bottom half of mounted rings (tops off) would get you close enough to see if you had an issue.


      • Gunfun1

        It can be done with LASER Collimator and Vs
        It also takes a precise routine and attention to detail.

        I liked the fact that you moved the discussion from theoretical perfection back to practical shooting. It kills me how hard folks work on their gear and never can be bothered to devote at least that much effort into learning how to better read and shoot the WIND!

        END of Rant!

        Thanks for the Soapbox Gunfun1! ;^)


  10. BB,

    Here is another alternative to the Sportsmatch adjustable scope mounts.


    These work great if you do not have any “windage” problems.

    Now with the Sportsmatch you can set your scope to “optical center” (look it up here in the Search at top right) and almost zero your air rifle without touching the scope adjustments. They are nice.

  11. B.B. said, “If I’ve left something out or not explained it well enough, let me know.”

    I know that B.B. has given these tips previously but they do belong in Part 1 of this refresher:

    1-Use B.B.’s criss cross method when tightening down the screws on your mounts rings to assure equal pressure is applied to your scope tube.

    2-Once everything is set up, before you start shooting and adjusting your scope’s elevation and windage you must remove as much parallax out of your scope as possible using the ocular adjustment.

  12. At what distance do I need to be concerned about barrel droop and shimming the scope?

    At this time, I only shoot CO2 rifles indoors at 10 meters and haven’t noticed any problems with an un-shimmed scope mount or over adjustment of the scope tube.

      • Cloud 9
        Why. Is it droop or balistics?

        Chairgun does give a idea with there graphs.

        But try some targets at 10 yard increments at 20 to 50 yards. Aim at one dot in the center of each paper and tell me what happens.

        If you collect those papers and lay them in order side by side from nearest to farthest and connect the dots you will see the trajectory of the pellet.

        I believe your seeing trajectory. Not droop.

        • GF1, I shoot FT so i know where my pellets go every 2 yards from 10-55 yards. Once adjusting the scope to zero it to the barrel, I know the clicks or holdovers to put the pellet into the bullseye over that distance. I am not seeing ballistics. Tom will vouch for my shooting capabilities, but I understand the need to ask the questions.

          • Cloud 9
            Not doubting your shooting. What I was after was to bring some more thought process to things that can be happening but not easily picked up on.

            And yes I know my .25 Condor SS out to a 100 yards. And I have to say it’s one of the flattest shooting .25 caliber guns I have shot.

            Anyway all I am trying to do is see what kind of knowledge people could bring to the table today on this subject.

        • Gunfun1
          To borrow from Jeff Foxworthy –
          If you mount a scope on your rifle after centering the crosshairs by counting the clicks, and measuring the distance of the lines thru the center of the scope and the center of the cylinder (let’s say 2.5 inches), and you place your target 10 feet away, and your POI is over 2.5 inches lower than the POA , so that it takes roughly 60 or more clicks to bring it up to 2.5 inches, you might just have droop.
          (Note that 2.5” and 60 clicks are just arbitrary numbers I’m using here and most likely will be different for you in actuality. Apologizes to Jeff Foxworthy and to everyone else for this run-on sentence.)
          from Algona

          • LarryMo,
            I have my Urban’s scope zeroed at 30 yards. This gives me a PBR with a 1″ kill zone of 11 yards to 37 yards. When pesting sparrows from my woodpecker feeder in the front yard at about 12 yards, I have to use a holdover of 1/2″, or 1 mil-dot. At 10 feet, the POI would be about 1.4″ low. This is based on my scope height being 1.9″ above the centerline of the bore.
            Until I understood the need for holding over at 12 yards, which seems counter intuitive, I had several misses. Another lesson learned.

  13. When ever I mounted my scope to my bulldog I was extremely careful to level my scope. The odd thing is, almost everyone I let shoot it tells me my scope is on crooked, but when I look at almost of their guns, the scopes tend to be at some weird slightly off angle. I seriously doubt its me, then there’s the fact my bulldog is spot on from 15 yards out to over 100, accounting for drop of course.

      • I suppose it could be. But I’ve leveled the gun with a spirit level in relation to the ground, then leveled the scope to that. I’m fairly certain none of them have bothered doing any of that. I’m the only person I know directly that actually bothers doing anything of the sort, carefully leveling with a spirit level so the scope is truly level.

          • And then, I’d bet, they are the ones who complain that their scopes run out of adjustment or have float withn the optical tube inside the scope chassis.

            These things can be largely ignored, I suspect, for plinking or shooting fairly large game or pests, but 10 M target shooting brings out the worst of crude adjustments.

            No doubt, those who ignore the little things in set up will soon be blaming the manufacturer for defects in the products they buy and whine on blogs or bad mouth the makers to their friends. That’s not to say that manufacturers don’t make errors. I have found that Hatsan can’t make a .25 caliber bore correctly. Theirs seem to be over-sized significantly. But that came after loads of quality pellets would not work and then finding a size of deliberately oversized that do. The conclusion is obvious, but not readily apparent. One has to work at it.


            • LFranke
              See what happens at 50 yards.

              I had a couple .25 caliber Hatsan’s and they was not the best shooters I have had. They were springers though and not pcps.

              But I can say I have had several Hatsan .177 and .22 caliber pcps and they were accurate.

              I have been wanting to get a Hatsan. 25 caliber pcp. Now I don’t know if I should spend the money.

    • Aurontotcs,

      “When ever I mounted my scope to my bulldog I was extremely careful to level my scope.”

      I do the same but need to ask exactly what are you using as the baseline measurement? The debate has always been, for me, do I start with the bore axis and the perpendicular axis to that or to the line of sight from the scope. I finally thought about it long enough to be able to end the debate; i choosed the BORE AXIS and the reason is: i can do the least to change that over the life of the shooting system. IF you need precision then starting with one axis as the given is the only way to measure the fit or changes to the entire system from barrel BORE to Scope Line of Sight.

      Nothing else has ever satisfied the job in my mind.


      • The Bulldog I used as my example, you don’t really have easy access to the barrel, but theoretically the chassis should keep the barrel centered within its self. Since the chassis is molded rather than carved or machined out a natural material it should be consistent in keeping the barrel centered. I used the integrated picatinny rail as my baseline and leveled that. After the stock/barrel was leveled I placed the scope and leveled it along the same plane. I then checked it at 50 yards with a horizontal line and a spirit level on the gun and scope. Its probably not an approach that can be used on every gun, but it works for me.

        On my other guns I’ve chosen the flat machined on the top part of the barrel for your scope mounts to find what can roughly be considered centered, albeit depending on the rifle how true that is, is difficult to ascertain without using some higher end machinist tools.

      • Shootski: totally agree. The bore axis is the axis that determines where the shot will go (despite the vagaries of the various pellets themselves). I level/plumb, on my springers to the flat top on the breech block as the starting point since this is where that axis is held since the barrel is in it – the intractable reality. It seems, to me, at least, everything starts from that point and must be adjusted to that point.


  14. B.B.
    You may recall (or, not) that a few years ago I posited my theory that airguns were built with a slight amount of droop because it was more popular to shoot with iron sights rather than use a scope. To add to that Western stocks are much straighter than European stocks and are more suited for scopes. I had an episode the other day that really bore this out.
    I have a small assortment of rifles that I shoot offhand in my indoor range of 15m. I personally don’t like shooting offhand with a scoped rifle so I started with all of them using iron sights except for my FWB124 and FWB127 that were converted to peeps many years ago.
    I had one rifle that was a problem with open sights – my RWS Diana 34. It had absolutely no barrel droop (honest – go figure!) and I really had a problem scrunching my cheek down on the stock. I would even have to put my cheek bone beside the stock to get a sight picture. Oh, and I had to have the rear sight all the way down. Once I put a peep sight on it, most of the problem went away.
    from Algona

    • Larry
      That’s a terrible way to build a gun then according to your theory.

      Why biuld droop in the barrel? Why not change the stock design.

      Or maybe really it’s only the stock that is changing your line of sight with open sights.

      Why not scope height with a scoped gun then with line of sight.

      Maybe it really is line of sight that is making everybody think they have barrel droop? Of course that is if you prove that it isn’t actually barrel droop like we talked about above by actual measurements. Eliminate that factor then your theroy could be right.

      • GF1
        I totally agree with you. All I was saying is that Americans demand scopes, and their stocks reflect that. If you look back thru history, you see how stocks have evolved. They were much more sloping downward prior to scopes so that as you mounted your rifles your eye came in to line with the iron sights. As more and more Americans turned to scope use the stocks evolved to the “western” style which is much straighter and raises the eye higher in relation to the sights. Mostly, a European stock that’s not for the American market has that “hogback” slope that makes Americans go “Eww, that’s ugly!”
        Anyway, that’s totally my point. Keep the droop (for iron sight use) or change the stock. I’m a little surprised you have any doubts about barrel droop. I thought that was accepted as a universal truth by now.
        BTW, I sure wish there was some way I could get you to try the triggers on my two older FWBs. I think your daughter would love them. Way back when everybody was discussing here how great the Rekord and T06 triggers were, I mentioned that my FWB 124 & 127 both had triggers adjusted like they were “set”. They perform exactly like you described herein on post further down about how your daughter liked the trigger on the Gauntlet. There is one exception. My triggers reset themselves back to the first stage if you totally let off the trigger. When you hit where it “set” then it is just a slight pressure to release. When I made that comment here, absolutely NOBODY made a comment, even if to say they thought I was crazy. So, in the mean time I bought an HW95 and a Diana 34 complete with the aforementioned triggers. I also purchased a FWB Sport to compare the newer triggers on them. To add to the mix I got a Hatsan 95 for the Quattro trigger, a Mike Melick tuned trigger similar to the old T05 on an XS25 (Diana 34 knock-off) and a Walther Terrus for whatever it is they call their trigger. I think I read somewhere that the new FWB Sport has a trigger like the one on the FWB 300. Don’t know. Anyway, I still prefer the triggers on the FWB 124&127.
        Take care/Stay healthy.

        • Larry
          I have a FWB 300. Both my daughters have shot it too. They think the trigger is a little light for them. But they got use to it.

          And yes I believe guns have droop. But I want proof the gun truly does have droop or not.

          If the gun doesn’t have droop. Then what is causing the same type of sighting problem with a gun?

          • Gunfun1
            I have the same problem with the trigger on my FWB Sport. I try to shoot my airguns daily in rotation and when I get around to the Sport, if I don’t remember (very likely now-a-days) the first shot goes off before I’m prepared. Fortunately, I’ve trained myself to not put my finger on the trigger until I’m on target so I don’t put (any more) holes in the wall.
            In the conversation about droop, I’ve always followed the 10′ target method outlined by LFranke (and, previously by B.B.) above and droop is moot. As far as figuring it all out I’m afraid that now-a-days it is far above my pay grade and also IQ.
            from Algona

            • Larry
              I shoot my air guns in rotation too.

              And like you. I learned to keep my finger off the trigger till I’m ready to shoot my FWB 300.

              Definitely easy to bump the trigger at the wrong time with that gun.

      • Gunfun1,


        But with most iron sights the front and rear sight are mounted on break barrels on top the barrel assembly. The only issue then is that the BORE AXIS is seldom (NEVER) parallel to the outside of the barrel. So they let the barrel droop since with lots of cocking cycles it was going to droop anyway.


        • Shootski
          Yep I see that. But read my question right above to Larry.

          What if the gun is proven to not have barrel droop but still shows it when you shoot the gun.

          What then is causing the effect of barrel droop?

  15. Ok after talking to Cloud 9 above I have to say this about our discussion we all gave been having about barrel droop and canting and balistics and left to right centering of the scope or barrel.

    If all this don’t make you think about scope mounting I dont know what will.

    But here’s the thing. When it sall said and done we learn how to make adjustments and such to correct the errors and balistics the best we can.

    Its never as simple as loading a pellet and shooting. It looks that way. But the more you get into it and the accuracy bug hits. Things take on a whole different prospective. We just have to figure it out.

  16. Ya’ all might want to save this. I picked it up off another site. It has to do with diagnosing GUN CANT VS SCOPE CANT,.. OR A COMBO OF BOTH,.. and the results you get. By knowing this,… you know what to reverse or fix.

    The columns read as follows:

    scope cant – gun cant – close shots – far shots

    ( 0 ) = zero gun/scope cant, ( on ) = shot is on bull, ( r ) = shot lands right, ( l ) = shot lands left, ( cw ) = clockwise, ( ccw ) = counter clockwise, ( + ) = more extreme cant

    ccw-cw-l-r *

    For example,.. use * (cw-ccw-l-r). Scope needs rotated CW and gun held more CCW (for) near shots to land more right and far shots to land more left.

    Never tested it,… but this seems? like it would be common knowledge? and probably already published? somewhere. As you can see, the first 2 columns cover any possible scope and/or gun cant combination.

    I am sorry it is not laid out better. 🙁


    • Chris USA,

      Hmmm! Not bad as far as it goes…

      However, it isn’t just a left-right issue there is a DOWN issue to CANT with a traditional Line of Sight over Bore arrangement!


      • Shootski,

        Glad you approve. If you know of an easy to read table that shows this/that (and more?),.. feel free to post it. It is not surprising that you could add something to it.

        You have provided many links,.. so maybe this is in one of them. I am still digging through them. 🙁


        • Chris USA,

          I’m not approving anything you do Chris…NOT in my job description! I don’t think any of us that post need anyone’s approval. I think we recently saw an unfortunate case of that; glad that doesn’t happen often here!

          I do have a link that has some stuff that helped me get my head around what is important in the whole sighting in thing. Benji-Don, Gunfun1, you and others have said a bunch of the same good stuff…but this guy has most of it and some great pictures too!



          • Shootski
            I read the article. Definitely a way to get you close on sighting. And it does say it’s a way to get the barrel and sights aligned at a given distance.

            Still not the same as what we have been talking about. The shouldering of the gun and the cant to the cross hair. And I would still like to see some tests with a gun that has actual proven barrel droop compared to a gun that has been proven that it doesn’t have barrel droop but still shows it when you shoot that gun.

            I want to know if ballistics and sighting can appear to be barrel droop when you shoot.

  17. I found it using a bubble level on the dovetail and aligning the scope reticle to that seems to work about the best. If I want to be more exact, then I use the plumbob method with the vertical line of the scope radical.


    • Shootski
      Great article. Took me back to my reloading/hunting days. I had 3 rifles – a .30-’06, a .25-’06, and a .22-.250. I slated them all for hunting so when reloading I was very meticulous. I even used a trickler when weighing powder charges. When I tested my loads at the range I was aiming (no pun) for a specific goal. The repeatability of the first shot. In other words, I was concerned that one round would hit exactly – to the best of my ability – on the POA, and so would the 2nd or 3rd should they be needed. Therefore, 3-round groups were the norm and if I could get them to hit the POA then I was in fat city. I would measure my groups and adjust my sight based on that. I also was quite honest with myself in my limitations. I didn’t expect to shoot the .30-’06 any more than 250 yards or the .25-’06 over 350 yards and knew that 95% of my shots would be much closer that that for either. Even if I was stalking antelope I would hope to get within those limitations. All rifles were(are) bolt action so bore-sighting was easy for scope mounting. I never worried about cant. In fact, with the peep sight on my service rifle and putting the peeps on my air rifles, if the front sight looks vertical I’m a happy camper.

  18. Off topic:

    Just saw a news feature on the evening news that showed how you can deliver Halloween candy to the kiddies in a “safe” manner this year.

    A fellow attached a 8′ shipping tube (4″ diameter) to his hand rail. Throw the candy down the tube.

    Just an fyi for anyone that wants to participate this year,… if you have it.

    I live (very) rural and have never had a tricker-treater in 14 years. If a squirrel ever came a knockin’,… it would get a very special treat,.. delivered via .22 Maximus. 😉

    Second thought?,… that squirrel would be worth a million! 🙂


    • Shootski,

      “I don’t think this guy is/was a shooter….” Whoever said that he had to be? Just have to be a good salesman or have the right “connections”.

      I currently have a 3.2 million dollar application into the federal government for a 2 year study on slugs in my tomato patch. Approval expected any day!


        • Shootski,

          Shishh! That is a given!!! I was thinking more along the lines of lasers, nerve agents, buried electrical high voltage lines,…. you know?,… the basics. Ok,… exotic basics. Then again,… coffee grounds might just be “exotic” enough for the Washington crowd? I am not so sure that they are too in touch with the common folk that garden and such.


          (my garden area gets coffee grounds all year long)

          • Chris U,

            How did your peppers turn out this year? I planted less but they have produced well. Kate made a great chillie relleno casserole out of poblanos and jalapenos a couple of days ago. I now need antacids but it is so good. I been trying to develop a strain of my favorite peppers but they cross breed so easy making that difficult.

            I have one volunteer pepper that is a big flat pepper like a big Jim I am going to save the seeds for next year. The plant only had two peppers this year and I gave the first one away so I don’t even know what it tastes like.


            • Don,

              My 3 Ghost and 4 Cayenne plants did well/are doing well this year. I have 4 quart freezer bags (of each) stuffed full in the freezer and should end up with at least 2 more of each.

              Everything will get turned into hot sauce later this fall with about a 1/2 quart bag (of each) saved back for chili and such.

              Jalapenos and Pablanos are common in stores, so I don’t bother growing stuff I can easily buy. I potted all the pepper plants this year. They require almost daily water, but the plus side is that they can drain well if we get a bunch of rain.

              Glad yours did well too. Did the cabin escape unscathed?


  19. As BB stated this blog was mostly intended for new shooters so what I have to say may seam obvious to most. 😉

    No mater how accurate your scoped airgun is NEVER shoot anything when you can see a vehicle with it through the scope. Especially if your target is sitting on the roof, poking its head out of your 69 Mustang hood scoop or standing in front of a tire. Flyers and pellets passing through the target will bite your … cause regrettable problems 🙁
    Murphy’s Law is still in effect !
    Bob M

  20. Ok you all.

    I just got to say this.

    When I was growing up I remember my dad talking about things with shooting.

    But I never thought about all this stuff we are talking about these last few days. I just shot and I shot with what I could afford which wasn’t much back then.

    But here’s the thing. I did well enough for the type of shooting I did.

    My problem now is I have been exposed to too many variables. Now I think probably way more than I need to. But to me that’s ok too. How else do you have fun and learn??? Experience

    • Gunfun1,

      Double Yup! I think we used to learn lots of things by the apprenticeship type of learning. Then some Educationists (the ones that couldn’t do, decided they need work, so the started the Classroom education movement) lots has changed…now some kids think you need to go to University to get ANY RESPECTABLE job…look at all the Ubber Drivers with four or more years of college!

      BUT to get back to airguns i have an idea! To figure out if a gun is a real drooper shoot it right side up, roll it 90° shoot again, roll 90° more (upside-down) roll 90° more and finally roll 90° more (upright again) and see if your pellet’s Point Of Impact (POI) make a circle around the Point Of Aim (POA)…I would do it but i don’t own any droopers!


      • Shootski
        I like your idea of rolling the gun and shooting.

        But a 180 would be only what we need for droop or now it would be barrel rise instead of droop.

        But remember we are talking about a scope to see if balistics and line of sight causes the droop effect.

        How the heck we going to look through a scope with the gun held upside down and get good cheek weld and all that other stuff we know about?

        And don’t tell me to do a head stand on my shooting chair. 🙂

        Man O man all these scientific experiments don’t come easy do they.

        • Gunfun1,

          I suspected you would ask something like that so i gave it some more thought.

          “And don’t tell me to do a head stand on my shooting chair. ” Would I do something like that! Lol!

          It would be best to take the action out of the furniture (stock/forend) and properly mount it into a ball vice that had the axis of vice rotation trued. The reason i went with the four 90° rotation stop points was to show that the droop was not just gravity induced but actually how the barrel to receiver block had been machined/assembled.


  21. Darn anyway. Just had another thought.

    How do you all make sure you don’t cant your gun when you have a red dot sight or peep sights on your gun?

    The big question is when you shoulder your gun.

    Do you unconsciously cant your gun and shoot as normal. Or are you aware that the gun is canted. How the heck do you know without the cross hairs of a scope?

    I just shoulder my peep sight and dot sights and shoot. Maybe I have been doing that wrong all these years.

    Someone enlighten me please to how they do those types of sights. Really I’m listening.

    • Gunfun1, I can’t address red dot sights as I have never owned one; but all my peep-sighted guns have thin front blade sights, so it’s easy to see if they are vertical or not…sorry; I know that’s not much help. =)~

    • Thedavemyster,

      The plastic from Clorox bleach bottles or protein supplement cannisters works well and cuts easier. The protein cannister plastic is black and would just disappear.


    • Gunfun1,

      The frame around the red dot has horizontals and verticals that your brain sees and you do it automatically if you let it. You know that EXPERIENCE = Automatic
      IF you learned how to do the basics right to begin with; sounds like your Dad did you a favor by teaching you enough to go on and finish the learning yourself. Hopefully you did it similar for your daughters!


      • Shootski
        When I shoot with my dot it is the round type. I imagine there is flat areas that my eye will pick up on.

        But I usually just shoulder the gun and shoot. I might be canting the gun for all I know. All I know is I hit what I aim at. So until I start missing I’m not worried if the gun is canted or not.

  22. “There is the shim I put under the scope on the rear ring. It’s a cut-up credit card.”
    I’m “late to the party” as our internet has been out; but I really like the use of that as a shim; sometimes, I will use a shim from a cut up soda can; but one time, that was not enough, and I had to use 4 layers of metal; a bit of credit card would have been easier. The next time my wife shreds our old credit cards, I’ll have to tell her to save me a 1/2″ wide piece to use for shims. =>
    Take care & have a blessed weekend,

  23. Has anyone ever considered that the air pressure pushing a pellet through a break barrel might also transfer that force to the barrel while the pellet is still in it and cause it to pivot ever so slightly on its pivot bolt? It could tilt the barrel down enough to shoot low and it would probably be more pronounced with a heavier slower pellet.

    That’s why SIG incorporated its Wedge Lock Breech System in its ASP20
    A spring loaded ball bearing or tapered wedge in a detent is simply not strong enough to prevent the barrel from tipping down some.
    Bob M

  24. Bob M,

    Never thought of that one; I’ll add it to all the other variables that are built-in to the breakbarrel airguns! I’m a firm believer in KISS which is why i have such a hard time in buying a breakbarrel; even the SIG ASP20! But, so far SIG AIR seems to have eliminated the drooper problem if all the reviewers are being observant.



  25. Shootski
    It’s not all bad. Break barrels have their own benefits.
    A solid locking device for the barrel would be perfect, but would probably require an extra step to unlock it, like a latch.
    If the droop remains constant for each shot it can be easily compensated for with droop compensator scope mounts or as mentioned here scope shims. Personally I don’t think shims are a good idea to tip a scope. They will obviously introduce some binding stress on the scope by not being aligned with the rings edges. It’s an easy cheep way out but a lot of people can live with it if it works with that airgun and has no major affect on the scope. Rings with inside padding or tape may help.
    I would imagine magnums and any higher powered springers are more likely to droop. Lighter pellets may reduce it some but they are ‘Not so pretty good” for the life span of a magnum which usually work better with heavier ones.
    Bob M

    • Bob
      I’m with you. To me shimming a scope is a bad idea.

      I should add to that. Shimming only the back scope ring to me is not good.

      If your having a issue like that. Then do it right and buy a drooper mount for your scope rings.

  26. B.B. et al,
    What I seem to see recurring mostly on this thread today is people’s concerns about “droop”. One thing that has not been mentioned is “barrel bending”. B.B. covered this quite a while back and has shown it is quite easy to do and is a good method for droop removal. Many years ago, for air guns, I dealt mostly with ARH. They supplied a service for a nominal fee, of scope mounting that included barrel adjustment for scope use. I am pretty certain that all he did was employ barrel bending techniques. In any case, when you got your rifle and scope you had full range of adjustments for your sights and barrel droop was non-existent.
    from Algona

    • Larry
      Good point. Don’t know if there is any info out there on a recommended procedure to bend a barrel. I would use something like a press with something between it and the barrel to spread out the force and avoid a real dent. Then bend a little, shoot a little and repeat till you succeed. I would strive for a gentle curve rather than a bend.
      Bob M

      • Bob M
        B.B. has already covered this. I’m not sure what the best search key would be but it’s here on the blog. He even shows a homemade press that gives it that “gentle curve”.
        from Algona

        • Thanks, Mike.
          I was wrapped up in something so I couldn’t try different things myself, but I wanted to get Bob started somewhere.
          All this talk about droop is just fanciful if people would use this method to keep their scopes from topping out. Of course, the best way is to just invest in a good set of adjustable mounts.
          Or, do like me and take all your scopes off and put on peeps or just use the iron sights. You’ll still have purchases that force a scope on you like the ASP20.

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