Aeon 8-32 AO scope with trajectory reticle: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Aeon 8-32X50 scope
Aeon 8-32X50 AO scope with trajectory reticle.

Part 1
Part 2

This report covers:

  • The test
  • First group
  • Power increased
  • Gun refilled
  • Last group
  • Results — wait a minute!
  • Conclusion

Today is the second part of the 50-yard test on the Aeon 8-32 AO scope with trajectory reticle, where I change the power of the scope to see whether the point of impact (POI) changes. You may remember last time the results were somewhat vague. Today we will double the number of groups shot under the same conditions to see if changing the scope’s power changes the POI.

The test

The test was to shoot two 10-shot groups at 50 yards with the scope set on 32 power and two 10-shot groups with the scope set on 14 power. I filled the rifle to 3000 psi and shot off a rest with the scope set on 14 power. No scope adjustments were made during this test — either last time or this time. The pellets I used are the same JSB Exact Jumbo 15.89-grain domes that were used in the first test.

First group

The first group was 10 pellets in 1.235-inches at 50 yards. If you look back at the last test in Part 2 you’ll see the POI has not changed much.

Aeon 8-32X50 scope group 1
With the Aeon scope set at 14 power, 10 JSB Exact pellets landed in 1.235-inches at 50 yards.

Power increased

Now I increased the power to 32X — as high as this scope goes. I noted that the parallax had to be adjusted when I got to the max power, but that may be due to my seeing the details of the target better.

Ten shots made a group that measured 1.063-inches between centers. The center of this group is about one-quarter inch higher than the last group. It’s almost too small to tell, but it is higher on the target.

Aeon 8-32X50 scope group 2
With the Aeon scope set at 32 power, 10 JSB Exact pellets landed in 1.063-inches at 50 yards. The center of the group may be a quarter-inch higher than the group shot at 14X.

Gun refilled

Now I refilled the Talon SS tank. It still had 2700 psi and another 20 good shots inside, but I wanted to shoot both groups with relatively the same air pressure.

This time I shot the first group with the scope set on 32 power and a strange thing happened. The group moved to the right noticeably! I’m inclined to say I think that movement is due more to filling the gun than to the scope adjustment. If I’m right, my SS doesn’t do its best when filled to 3000 psi. I won’t explore that today, but I certainly need to check it out sometime!

The new group at 32X was 1.884-inches between centers, which is WAY out of profile for this rifle — even for 10 shots at 50 yards. Something was wrong and I think it wasn’t the scope.

Aeon 8-32X50 scope group 3
Wow! What a result! With the Aeon scope set at 32 power, 10 JSB Exact pellets landed in 1.884-inches at 50 yards. The center of the group has moved a half-inch to the right!

Last group

I adjusted the scope back to 14X and shot another 10 shots. These went into 1.391-inches at 50 yards. The center of the group is almost exactly where it was for the first 14X group.

Aeon 8-32X50 scope group 4
And there you go. With the scope set to 14X the group is back where it started.

Results — wait a minute!

So I’m looking at the target through my spotting scope, trying to make sense of what has just happened when my shooting buddy, Otho, turns to me and tells me he has just had a major group shift when he changed his scope’s power. Otho is shooting a Ruger M77 in .220 Swift at a target at 200 yards. He tried it on 8 power and again on 32 power and the 5-shot group stayed under 2 inches, but moved 3-1/2 inches to the left! He was unaware that I was testing the same thing at 50 yards. We had talked about the possibility of groups shifting when the power of the scope is changed many days earlier, and he simply wanted to see it for himself. A lucky break gave me the startling results I was looking for.

That puts the end to this test. At 50 yards the results I got from both my tests were vague at best. But at 200 yards with an accurate rifle, they jumped off the paper! That leaves me with one conclusion for this question of scope shift when the power changes.


Your groups will shift when the power of your variable scope is changed, but the amount of the shift will be small at close range — 50 yards. Only when you stretch out to long distances with this shift become so important that you need to pay attention.

As for the Aeon 8-32 scope, I found it to be compact, clear and easy to use. The crosshairs are on the thin side, so you need lots of light when using this scope. The reticle is overly complex on this model, but optically I like the scope as much as any top-flight UTG or Hawke. I would not hesitate to recommend this scope.

69 thoughts on “Aeon 8-32 AO scope with trajectory reticle: Part 3

    • Hi BB, just wanted to say thanks for all the great information you post on a regular basis! I first started reading the blog about 18 months ago and probably 95% of what I know about air guns has come from from you and the great group of regulars sharing their wisdom. I started off with the Benjamin Trail NP pistol after reading your test and just today received the Gamo Compact pistol (from Pyramydair of course) and look forward to improving my accuracy and someday entering a 10 meter competition. I’ve spent so much time reading the blog, I feel like I should have a associates degree in air gunning! What a great advantage to have when learning to shoot properly! Thanks again!

  1. I’m glad you got to the bottom line on variable power scopes! The 3-9×50 I have on my Regal is the first one I’ve ever used, it used to stay on 3x but it’s been on 6x since this subject was last visited.
    I’ll have to see how much it could vary.

  2. How often does that happen in the field where one changes scope magnification? Usually I just leave it fixed at a magnification I prefer. If I wanted a closer look that is what spotting scopes and binoculars are for.

  3. BB and all,

    In the recent blog on lawsuits, you talked about gravity feeding systems. I ran across an interesting video of a Colette Gravity Pistol on you tube that used a gravity feeding system that dates back to the 1850’s. The powder charge and primer were contained in the base of the bullet making it a caseless cartridge. The gun held 20 low power cartridges and was intended for parlor shooting. It is a fascinating video but I wish they had cartridges and actually had fired the gun.


      • BB,

        When I was reading the description and they called it a parlor gun, I had an immediate mental image of you in your parlor (living room) with your trap set up and shooting the gun (and the cats leaving for parts unknown).

        There some very interesting designs. I’m glad I found that you tube channel. I subscribed so that I can go back and look at the videos for some of the other forgotten weapons. I want to check out the one for the 22 that Daisy put out. I’ve read about it but have never seen a video of it.


  4. BB
    You mentioned when you changed your fill pressure that your group changed. Rifling and power I believe is what’s happening there. I seen that when I shot the 2240’s that I had the steel breech and Discovery barrel on it with the 1399 stock and still shooting Co2. Also seen that when I converted it to the HPA.

    I also had the same set up on a few 1377’s and the POI would change side to side with different pumps in the gun.

    And whats the moral to this story anyway with POI and magnification change?

    ( zero your scope at the magnification you will be shooting at )

    • >And whats the moral to this story anyway with POI and magnification change?

      >( zero your scope at the magnification you will be shooting at )

      That is a good conservative and quite well motivated approach, Gunfun1. Do the same with the parallax focus while you’re at it. (Focus it at your zero range and leave it!)

      However, If you have a Zero-Point and learn a few techniques to use it as a “riflescope optics lab in a pocket,” you can characterize your scopes and learn how to mitigate errors sometimes. You could also use a bench rest, bore laser, and graph paper at a distance too, but it will take longer.

      I have yet to find an AO scope (the kind with the rotating objective) that could be focused over more than about 1/2 of its range before exhibiting at least a “click” or two of error (and most AO scopes are far worse). Accordingly, most AO scopes cannot be focused from more than say 10 to 30 or maybe 50 yards before the adjustment error starts to make a good shooter look not quite so good! Though typically not as bad as AO scopes, side parallax adjust scopes typically have a few or even several “clicks worth” of error from one end of their range to the other too, but the error is typically only in elevation and it get buried in a shooter’s elevation “dope.”

      As I mentioned in my other post here, avoid the zoom magnification stops and always end adjustments in the same rotational sense. This is true for E/W dials too. Usually a good strategy is to go past your desired setting and then terminate the adjustment in the direction that tightens the erector spring (down and left POI where you are, mnemonically “screwing the dials into the scope”) but not always! I have a scope that likes down and right or it will be vulnerable to a “latent” shift in the future, which occurs the NEXT time I adjust my E dial. There is no way I would have ever identified the characteristic of that problem without my Zero-Point! Well–maybe I could have done it with a bench rest, bore laser, and graph paper at a distance, but I can easily check so many things and combinations of things using the Zero-Point.

      • Cal
        I know we had a conversation in the past about the zero point. And I agree with you that it can show the reticle shift and the parallax also.

        Definitely a good way to know if the scope is repeating itself.

        But throw in the ballistics of the projectile and its variables. And then I believe you have the conditions involved that BB mentioned when he filled his gun up and what I mentioned I have seen with multi pump, Co2 and pcp guns.

        I believe that if a person shoots enough airguns or firearms that you will start noticing that your group’s have moved on the paper. And exsperince will help you determine what caused that movement.

        But on the other hand the zero point will help you indetify the variable of the scope error. So at least you know when you see your group change location on the target you know if it was caused by the scope or other changing conditions.

        All in all interesting information.

        • I just tested CPHP 7.9’s against 9.8 Winchester round nose again in my QB-88 and since I have the sights set for The 7.9’s I noticed a 3/4″ drop in the first 8yds. I’d be losing a lotta elevation by using them at much further range

          • Reb
            I don’t know if I buy that thought completely.

            The arch of the trajectory of the heavy pellet will be different than the lighter pellet.

            So depending on what distance you zero the heavier pellet will determine how far above and below the reticle center horizontal line the pellet will fly.

            You have to determine the best zero distance for each weight pellet you use. Well even what shape pellet you choose.

            And here I go again. Chairgun will help you see that with the graph it gives.

            • I’m getting ready to order more pellets to test in it of course the 10.34 JSB’s will be one of those especially since the QB-36 does so well with them even though having less power to push them with. I’m thinking somewhere between 8 & 10 grains is gonna be about right. I need more Winchester’s and more 10.34’s but I’d better get some of the lighter JSB’s

  5. BB
    Also I
    remembered in part 2 I asked about if you tryed adjusting the parallax when you changed magnification.

    Well you shot it first the same as last time then you turned the magnification up and noticed you needed to focus the parallax better. You shot at the higher magnification then went down to the lower magnification and left the focus alone it sounds like to me. And the groups were in the same place as before you did your focus on the higher power. So that means the refocusing did not change the POI.

    Anyway interesting test.

  6. >Your groups will shift when the power of your variable scope is changed,

    Of course this doesn’t happen with all scopes but it is, I’m sad to report, common enough (as are shifts and hysteresis/”slop” in E/W controls). Again, I’ve found parallax adjusters to more often cause shifts and the shifts are particularly nasty when they contains a windage component. (It is a universal problem with objective bell/ “AO” style scopes and I’ve yet to evaluate one that didn’t have the problem.)

    By the way, magnification zoom induced shifts often occur as the zoom adjuster ring hits its stops at either the upper or lower limits of the zoom range, or sometimes the shift occurs when changing direction in the rotation of the zoom ring. These errors can be mitigated by avoiding the stops or always finishing a zoom adjustment in the same rotational direction. With some scopes though, all bets are off and there is no way to mitigate a shift.

    I guess I own close to two dozen riflescopes myself and only two of them produce no opto-mechanical errors that I can detect with my Zero-Point and the two are also perfectly calibrated (magnification, E/W clicks, reticle subtensions, etc.). They are my Leupold Mark 4 MR/T 2.5-8×36 and my Vortex Razor 5-20×50. Gee–what a coincidence; they also happen to be my most expensive scopes! On the other hand, errors are common in the less expensive other scopes in even these two company’s products lines (the low-end Crossfire series and even the much pricier Leupold scopes with adjustable objectives, for example).

    All I ever read about is “glass” and image quality in online reviews. Most scopes have pretty good image quality these days (it’s certainly adequate most of the time) but mechanically, most scopes have shortcomings–shortcomings that can affect a good shooter’s performance, unless they set their scope’s dials and rings and never touch them, which I guess is a practice that can be performance-limiting in itself.

    • Cal
      I switched to side parallax scopes verses front parallax for more than one reason.

      First was ease of operation because of where its located on the scope plus the option of putting a big wheel on to allow for finer focus adjustments which I believe helps you reapeat your focus more consistently.

      And second thing was when I did get back into air guns I did alot of grahping my pellets flight with targets at different distance. The side focus scopes did seem to repeat better than the front focus scopes.

      All in all I believe the more you know how your equipment works the better job you can do with it. And I’m not just talking scopes or airguns. Pretty much anything a person does.

  7. Just a thought: Wouldn’t the easiest way to check this be to hold the scope in a vise, point it at some kind of “test pattern” and then to see of the reticle “moves”?

    Well, easy might be relative because you would need a heavy table and a strong vise on the range…

      • I very much appreciate your real world testing for the kinds of problems I’ve been finding with my Zero-Point and the mount I carried around SHOT show for the purpose of testing as many scopes as possible this year. You are certainly a good enough shot that the errors are detectable. My shooting experience that got me beating this drum was more like Otho’s (a huge error), though I know he’s a good shooter and smaller errors would matter to him too.

        Your 1/4″ POI shift at 50 yards is about 1/2 MOA or “two clicks worth” of error for most scopes. I believe that scope manufacturers should strive to limit these errors to remain significantly smaller than the precision offered by the scope’s elevation and windage dials. Logically, dial granularity should be the factor limiting the precision of a riflescope, but rarely is this the case.

        In my testing, two clicks worth of this sort of error is actually pretty good scope performance, relative to the pack! Even so, given a 400 yard shot on a pronghorn antelope’s 8″ kill zone, it is 2 inches of error and an unacceptably large contribution to my error “budget!” For me to use that scope, I would need to either tape down the zoom ring with duct tape after zeroing the rifle, or further characterize the problem so I could mitigate it with some kind of operating procedure and rule. I’m actually getting to the point that I tape a card containing the scope’s operating rules right on its rifle in my gun safe so I won’t forget what is necessary to get the best performance from the scope.

        Maybe we now know why military sniper scopes are typically fixed at 10x power with fixed parallax focus. Personally, I’d rather have a threaded locking style eyepiece too, instead of a “fast focus” diopter adjuster. Who needs a fast focus eyepiece? The adjustment should be set, locked, and then forgotten.

    • Ck
      I’m with BB 100% about what he just said.

      Real world results. In other words shoot the gun and make your changes with the scope and see what the pellet does.

      Majic words. See what your pellet does.

      • At least it’s affordable to generate real world data when shooting air guns. For big game hunting rounds that cost $1-$2 per round (or slightly less expensive painstakingly hand-loaded rounds) it gets expensive! Or it gets expensive when shooting a $500+ firearm barrel that might only retain excellent accuracy for 1000 rounds or a little more. I also can’t shoot a heavy recoiling rifle (anything bigger than a .30-06) very many times without having to exorcise the resulting flinch command from my brain with several sessions of dry firing. One box of 338 ammo and I’m more than done with having fun!

        Finally, there’s the time involved to shoot for data. It just takes too much time to find many of the problems I’ve detected in scopes and it takes even more time to search for a mitigating operational rule. For example, B.B. would have likely discovered that bumping the zoom ring stops or a reversal of the zoom direction caused the problem, if he had a Zero-Point (and in fact they were the case). With the zero point, you look through the scope, adjust the controls, and instantly see the result. You do have to position the reticle against the background strategically to see the smallest errors and also make sure you don’t apply pressure to the scope’s mounting system (gently adjust and release, adjust and release) but the data is easy to acquire. You could even plot error vs. tank pressure in a PCP very easily!

        • Cal
          But see what happens when you throw the pellet flying into the mix.

          As I said before in the past with the zero point. All your doing with it and the scope is showing the scope errors.

          When you shoot a projectile the most important thing is where the projectile impacts the target. All I can do with the zero point is guess what the projectile will do.

          Please tell me if the zero point can predict the projectiles flight path with the variables that projectile can encounter in flight.

          • >Please tell me if the zero point can predict the projectiles flight path
            >with the variables that projectile can encounter in flight.

            Of course it cannot–it does something better. It eliminates flight path errors (shooter, gun, atmospherics, projectile, etc.) from consideration. When you wish to reduce overall error, it’s helpful (even essential, unless you like guessing games) to know where the error contributions are coming-from. Then you can address them.

            I guarantee you that there are correctable “real life” errors limiting your shooting performance that you will never be able to detect and correct by just shooting. The Zero-Point is just a tool (as are other similar tools useful for this purpose like graph paper, a bench rest, and a laser bore sighter). Other tools, including non-shooting activities, that can improve one’s shooting are dry firing, a good chamber reamer, various computer tools, etc. One could argue that dry firing has not purpose, because all that matters is hitting a target. Or you could argue that the computer tools that video record one’s muzzle track vs. the timing of the shooter’s trigger actuation are not relevant. Similarly, I shoot better, because I use ballistics software. There’s just not enough time in life to do it all by just shooting!

            The fact is no paper target is required to improve one’s shooting and sometimes paper even gets in the way of achieving that goal!

            • Cal
              Sorry but I just don’t look through the scope that’s mounted on my gun. I shoot the gun to see the results that the whole pakage gave me.

              Like I said before. It’s nice to know if a piece of equipment is performing like it was designed to work. But it means nothing to me until I see the end result of the goal I’m trying to achieve in front of me.

              Now as you say if there is a tool or gage to show me that my equipment may have deviation from how it was designed when its used. Well then at that time I have to decide if that tool found something that will affect my end result or if I can live with that amount of deviation.

              So I don’t understand why you keep bringing up the same points I made. And if you ain’t learned something from your targets then you ain’t looking at or don’t understand what that targets telling you.

              Sorry as I said before I aint just going to set down and look through my scope and not shoot a projectile. I have to shoot to physically know what the end result is. Yes we’re the projectile impacts the target.

              • >So I don’t understand why you keep bringing up the same points I made.

                Maybe it’s because I feel like you keep dis’n the benefits of my tools and methods and declare them as being of little value to you, compared to shooting. Perhaps they are of little value to you, but I keep thinking that you don’t understand their benefits, or perhaps we are in violent agreement and just don’t realize it.

                Most of what I “know” about shooting (which enables my shooting performance) I think I actually learned by NOT shooting! It’s sort of like how the great skier Jean-Claude Killy credited his world beating performance on his job driving a farm tractor all summer long (well–at least a little bit like it). While driving that tractor for hours on end, he skied “in his mind’s eye.” He said the results were almost as good as actually skiing and permitted him to practice far more than he ever could on snow.

                • Cal
                  That’s what I mean. I’m not dissing the tool.

                  I’m saying that it is doing the job its intended to do. Finding out if the scope will poduce the results it was designed for.

                  So at that point when I know what that scope is capable of from using your tool then I know if that scope is ok for the type of shooting I want to do.

                  After that is determined be it using that scope or getting a different one. Then I shoot and document results.

                  If I’m happy with them shooting results then great if I’m not happy then I make changes.

                  Is that a little more clear this time around?

                  • Yes and thanks. That sound like a perfectly reasonable approach, but even if you shoot the scope and document the results, personally I would still be interested in knowing the results from any tests performed with the tool.

                    If someone records and reports their personal racetrack lap times on a car race track, I would still be very interested in reviewing horsepower data obtained in engine dynomometer testing, and perhaps also the results of skidpad testing, 1/4 mile dragstrip times, etc.

                    • Cal
                      I drag raced at the local track for over 35 years. Dynoed many cars.

                      All I can say is the results at the track was surprising at times.

                      I think the best that can be said about our comments we do think there are use for special tools.

                      And we both just have different ways we would use them.

                      I would say it’s probably as usual personal preference of how a result is acheived.

                      Thank God for choice.

                    • CalinB
                      I have been reading yours and GF1 posts back and forth and first off I have one question which is, What is this zero point you are referring to is it a computer program or a physical tool that you use to test with.

                      GF1 and I both use Hawke scopes Chairgun pro and BRC software to plot pellet trajectories for our guns, scope and pellets by inputting data into the program to see the estimated results of the inputted data.

                      I use it extensively in my FT shooting to tune my PCP guns to shoot to the trajectory I want/need it to shoot at to hit my targets from 10 to 55 yards and while it is just an estimating tool it is very close to real world results.

                      At this point until you explain what the “zero point” you keep referring to actually is I will have to side with GF1 in that all the tools available to us for use are just that tools and do not or cannot be better than real world shooting and testing to see the true final result.

                      There are variables that no tool or software can predict to a 100% accuracy as the weather and wind conditions are a constantly changing variable that is never constant or predictable to 100% certainty.

                      Please explain this “zero point” you refer to so I can understand your side.


                    • BD,

                      The Zero-Point is not a prediction tool or a simulation, though I make extensive use of ballistics software too. It was discontinued from the Leupold product line a few years ago. Prior to that, it was sold and marketed as a rifle zeroing aid and also as a means to re-establish a recorded zero on a rifle (which it can usually do within about 1 MOA, if carefully used). For single session measurements relative to each other, I can detect as little as 1/4 MOA or less in reticle shift and errors using it. Hence, I use it as an “optics lab in pocket” most often, instead of for Leupold’s intended purpose. There is nothing in the following two references that describe how to use it as I use it, but they’ll give you some idea of the Zero-Point’s features and design:



                      Perhaps I’ve mentioned it before but I can determine whether a scope is calibrated correctly. For example, are its E/W dials calibrated in IPHY (“inches per hundred yards) or true MOA or not calibrated at all! You’d be surprised how many E/W dials are mis-labled both ways! A 0.047″group shift is very difficult to detect at 100 yards by shooting (probably even impossible), but it becomes significant when you have to dial more than a full rotation of elevation at 1000 yards! Sure–your could shoot a couple boxes or more of ammo at 1000 yards too, and perhaps detect the error, but you could not quantify or characterize it as well as I can in a couple of minutes using my zero-point!

                      I can also check a mil-dot or other reticle for calibration and accuracy. You might also be surprise how many scope need to have their magnification set considerably different from what is published as producing mil-dot subtensions in a 2nd focal plane scope. Many similar checks and evaluations can be conducted with the Zero-Point–even more so than using a laser bore sighter and graph paper for a number of reasons.

                      >At this point until you explain what the “zero point”
                      >you keep referring to actually is I will have to side with
                      >GF1 in that all the tools available to us for use are just that tools

                      You can side with whomever you please. I really don’t care one way or the other. Perhaps I’m wasting an awful lot of my time posting to B.B.’s audience! My write-up are often very time consuming. I think I was able to convince Mel of of the value of the Zero-Point (he writes excellent reviews of riflescopes and other shooting hardware there) and I think he is now looking for a Zero-Point on the used market. The technical staff at Vortex Optics use several of them for exactly the purposes I’ve described in B.B.’s blog too. I’ve had extensive conversations with their technical staff, because I originally discovered what I call “parallax adjuster induced “reticle wandering” on their Crossfire scopes.

                      Again, I really don’t care what you or GF-1 believe. I use my Zero-Point as an error measurement tool It’s not a prediction tool or a training tool. I used dial test indicators to measure the runout of barrel chambers and tenons or the squareness of a receiver face too (as I’m sure GF-1 could do too.) Maybe I should just shoot the rifle at let it go at that, before I re-barrel it! As another analogy, I’ll ask whether or not you would be interested in weighing or otherwise measuring pellet samples to find a good quality product or do you just shoot tins and tins of them and rely on the results to make that determination? That sole method has some merit when evaluating airgun pellets, but it would be a very expensive proposition, if applied to riflescopes!

                    • Cal
                      I just have to ask what do you do with these rifle scopes that don’t work out according to your zero point tool.

                      Do you send it back to the manufacturer and tell them that you checked their scope with your zero point and found it not true to the way it should work. And you would like another one.

                      Or do you keep spending money on another scope and do that time after time until you finally buy one that matches what your zero point reads.

                      Sounds like if you was to keep buying that could run into more money than shooting.

                  • >I just have to ask what do you do with these rifle scopes that don’t work out
                    >according to your zero point tool.

                    Hmm…am I still reading more implied skepticism from you Gunfun1? Perhaps skepticism is not what you intended here but it’s not just “according to my zero point tool!” I’m stuck with the scopes I had before I learned how to check for these kinds of problems and they don’t shoot as well as well as my good scopes. They exhibit errors that correlate perfectly to what I measure with the tool. Irregardless, If you measure the compression in your drag racer’s engine and the compression is down 50% in one cylinder, your engine is malfunctioning and it needs work (probably rings, valves, or perhaps a leaky head or head gasket)–and it’s not just “according to the tool!” Sure–you’ll almost certainly notice the impact of the problem when you run it at the strip, but why bother to race it in the first place?

                    Vortex customer support, with their excellent warranty and customer service, said they’d happily take my two Crossfire scopes back for service, because of the AO induced reticle shift problem, but they also very honestly admitted that they didn’t know if they could do any better and I declined to send the scopes back to them. I now don’t use the AO for large adjustments and I accept the small usable adjustment range along with its resulting small error. My Vortex Razor is perfect in my testing, so no complaints there.

                    For some of my scopes, I’ve used my Zero-Point to discover how to operationally mitigate their errors, but it’s not always possible. In my experience, many manufacturers will just return a scope under warranty with the same problem (and not admit their limitations as Vortex truthfully did). One exception was a UTG Leapers Hunter scope that I own. It has an AO style adjuster and with an associated error of the typical several MOA of reticle shift / error across its adjustment range. I sent it back to UTG Leapers under warranty and a replacement came back with far, far less error. The replacement has somewhere around 1 MOA maximum error and I’ll just live with it by limiting my AO adjustment range to something producing tolerable errors.

                    That Leapers scope is not the lowest AO-induced error I’ve ever measured, however. I have a BSA Platinum that BSA sent to me to replace a warrantied model that’s no longer in production. (I sent it back for severely mis-calibrated ballistic dials that didn’t even come close to matching their supported 223 Remington loads.) The BSA Platinum replacement scope suffers from only about 1/2 MOA error across its AO adjustment range–or the equivalent of about four of its ~1/8 MOA clicks. Most AO scopes, including the three relatively expensive Leupold AO scopes I’ve tested, are far worse and only a few side parallax adjuster scopes that I’ve tested are better!

                    Most of my testing was performed on the 2015 SHOT show floor, where I tested about a couple dozen scopes. I could tell you some stories about my adventures there but most of the vendor reps were willing to accept my evidence and claims in the end. The only exception was U.S. Optics where the company reps were completely unwilling to take their blinders off and accept that I had found an imperfection in their scopes! I’ll never buy a U.S. Optics scope now, but I will buy many more Vortex scopes, I am sure. Vortex listens! UTG Leapers also listens. Although I did not find a perfect scope in the UTG booth, the scopes I tested there were very good–especially for the money. Again, I must reiterate that I found several $5000+ scopes that exhibited discernible errors (though universally small errors in that price range) at SHOT.

                    Of the last five scopes I’ve purchased, I’ve sent four of them back to the online retailer for a refund. I don’t need to mount a scope conventionally to test it, thus nullifying a retailer’s return policy and perhaps damaging the finish. There’s no reason that I should keep a poorly performing scope, given retailer return policies. I tell them the results of my testing and send it back as defective. The last scope of the five is my Leupold Mark 4 MR/T. It doesn’t have a parallax adjuster and it checks out perfectly in every respect. I’ve given up completely on AO scopes and will only buy side parallax adjusters from now on, but even then I will probably be returning scopes in the future for side-adjuster induced errors or other inaccuracies. A scope that exhibits several “clicks worth” of error when operated normally is a sucky scope (which is, very sadly, most of them)! I used to scoff at online alleged scope aficionados dissing cheap scopes, because their glass is so inferior. What I’ve discovered is the glass (image quality) is almost always perfectly adequate and the aficionados are splitting hairs in many cases, but the mechanical inaccuracies suck and few people realize the extent and significance of them in a shooter’s “error budget!”

                    • Cal
                      Ok no need to go any farther here.

                      I can clearly see from your comments of what you expect from a scope and how you use it.

                      And believe me no sceptisim. I believe that the zero point is good enough for you and how you use it.

                      And as it goes for me I will just stick to the good ole fashion way of learning about how my scope performs on my gun.

                      Shooting it.

                      Out of here. Oh and have fun shooting.

                  • >I can clearly see from your comments of what you expect from
                    > a scope and how you use it.

                    Yes–when I shoot with a riflescope, I like to use its adjusters and not experience the few to several MOA of error that adjustments induce in many (perhaps even most) scopes, as B.B. and Otho experienced on the range and B.B. reported here.

                    Like you said, thank God for choices!

  8. Might even be interesting to see what effects are caused by shimming a scope . Flexing the tube under shim pressure might cause focus and zoom adjustments to get really squirrely .


    • One of the Vortex tech guys was telling me about this problem. Apparently, ring misalignment of even their big, heavy, and strong Razor scope can create this problem. We were talking about the Razor’s side parallax adjust and he told me that a bind on the rings can cause the mechanism to have enough slop to cause errors. It takes very little alignment error in the “rack and pinion” adjuster system to displace the optics inside. In a nutshell, yes–it gets squirrely!

      It’s why I have taken to bedding my rings with epoxy (or using the Burris Pos-Align) instead of shimming them.

      • Thought about that too , and with a release agent on the scope tube of course .

        I have gone to mostly the rings with the no slip tape because of my springers . The stuff smashes and form fits to a reasonable degree . Epoxy bedding would be the last resort if it seemed necessary .


        • Yes–I use a release agent on the scope and simply dedicate the rings to the gun (the bedding epoxy remains stuck to the ring halves). I’m getting 30 or even 40 MOA over 4 inches with no problems.

          However, I plan to try release agent on the rings someday too. Perhaps I can make removable, custom, no-stress shims that way.

        • Twotalon,
          There are two products that i have become personally familiar with over the years that you may wish to try. For a release agent, it is called DGF which stands dry graphite film, it sprays on, dries almost instantly and is simple to remove, it can be found at NAPA stores. The other product is an adhesive which I believe would work very well on scope rings to prevent creep. It is manufactured by 3M and called 847 adhesive. It is a high temp adhesive that is quite viscous initially then dries to semi hard state. A mere drop at the bottom of the rings would be sufficient, however, removal would require a powerful solvent such as acetone or lacquer thinner.


  9. BB,2Talon–Re shimming a scope– That is one of the reasons why I use Burris Signature rings with the offset rings. The scope tube is not flexed or bent. BB- Is the scope that you used shimmed ? If it is, can you retest with a drooper mount, or with the Burris rings? Ed

  10. GF–TT–GF, I agree. TT–I did try lapping. When I got perfect alignment, the rings were enlarged, and I Had to use shims to keep the scope from rotating and shifting when I fired the rifle. In addition, there were gaps where the rings did not make complete contact with the scope tube. I wish that I worked for Burris, they should have a more aggressive advertising campaign. The local gun shops (the few that are left), and the ” goose berg” store will get Burris products on order (don’t hold your breath while waiting), but they don’t have them on the shelf. Naturally, most of their customers buy whatever they have in stock. Never trust a salesman. They will try and sell you what they have to make a quick sale. EXAMPLE—I met a novice, first time hunter (in Canada) who was hunting moose with a .22-250 cal. rifle. He said that the salesman told him that it was so powerful, that even a near miss was enough to kill a moose. I asked him if there were any other rifles on the rack in that store. He said that all he saw were shotguns! The moose that he wounded was lucky. The novice had a buddy who killed it with a Winchester .300 magnum. He was sitting on the ground (the buddy,not the moose) , crying , holding his shoulder, and bleeding from a half moon eyebrow cut. He was also a novice, and bought the only rifle on the rack in another store. He told the salesman that he had shot a Daisy, and a pump pellet gun. The salesman told him that the .300 mag. had a little more recoil than the pellet rifle!. He also told him that there was no need to test the rifle, the factory had already zeroed the rifle! Was it P.T. Barnum, who said ” Theres a sucker born every minute, and 2 to take him” ? If I continue, I will have to change my sign in to the raconteur (not to be confused with racketeer or rocketeer( although I have made and shot off enough rockets to use that name) Ed

  11. Can we try this same test with a airgun that does not have the variable pressure that a PCP has?
    An accurate springer such as a TX200 or similar would help narrow it down if it is the scope or the rifle.

    Silver Eagle

    • Silver Eagle,

      Welcome to the blog!

      Yes, we can try this with a spring rifle. I’m going to the range tomorrow if possible. If the wind is calm maybe I can try it then.

      My TX is set up with a Hawke 4.5-14. I can try it at 14 and 6 power.


  12. If only I had a 200 yard range to shoot at. I thought that the .220 Swift was a fad of the past. But I have heard that the Ruger M77 and .220 Swift can be an extremely accurate combination.

    Maybe this was dealt with in the earlier report, but I have trouble understanding a trajectory guide in the reticle. That would seem to depend entirely on the caliber you are shooting. It seems to be a problem for a ballistic calculator, not a reticle.


    • Matt,

      That trajectory reticle is so specific that it is impractical in most situations. I think it’s just a fad.

      But you can use it for multiple aim point with different guns, you just have to test them to see where their bullets go, relative to the reticle.


    • Matt61
      That’s right. A trajectory reticle has to be calibrated to a specific projectile.

      If the coefficient of drag would change or the velocity of the projectile would change then that reticle would not give true results.

      Of course you could map it out by shooting at targets at different distances and make a cheat sheet to correspond with the marks on the reticle. That would give you real world results of what your projectile flew like.

      That’s exactly what I do with the Hawke 1/2 mildot retical on my air guns. That way you know what each air gun does with your pellet you chose at the different distances you shoot at.

      • GF1,

        I was going to say the same thing, albeit in a less eloquent manner. The mil-dot or trajectory reticle are essentially the same, the later being a bit “busier”. Both seem to be good for shooting “hold over and under”. It seems that it’s all about how much “busy” you are willing to put up with.

        And yes, actual shooting and “cheat sheets” are essential. Per gun/per projectile.


      • GF1,

        Being a machinist, what do you think about Calnib’s comment about adjusting in one direction only,…over adjust,…and set final adjustments always in the same direction?

        It took me awhile to remember, but the shear I use at work always does this, (digital read-out). It goes out (past) what you punch in,..and then (comes back to what you set it at).


        • Chris USA
          Without me going back through and reading all his comments. What are you adjusting? Parallax/focus or your clicks when zeroing?

          Clicks when zeroing I always go past a couple clicks of how much I need then come back to what I want.

          On parallax focus I always turn down to the closest distance then slowly come up to when the object becomes clear and stop. I found if I go over and it gets blurry then all I’m doing is playing back and forth focus games.

          • GF1,

            I would suppose,….that it would be the same “theory” for all 3,……W/E and parralex.

            I would guess, that it’s all about taking up the “slop” the (same way) every time… more repeatable results.

            By the way,..Calnib and GF1,….good back and fourth on comments….2 different views on maybe??? the same thing.


  13. I have always zeroed my hunting rifle (Deer) with the scopes highest power. This is most often 9X or 10X since at a distance that’s the power I will be using. If the deer is close, any small difference in POI on a lower power won’t make any difference.


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