POI shift when changing the scope’s power

by Tom Gaylord
Writing as B.B. Pelletier

Part 1
Part 2
Part 3

This report covers:

  • The last test
  • TX200
  • First group at 14X
  • Second group at 6X
  • Third group at 14 X
  • The final group at 6X
  • Conclusions
  • Summary

This report is an unprecedented final look at how the point of impact (POI) changes when the power of a variable-power scope is changed. I linked to the 3 earlier reports in which this phenomenon was tested (it wasn’t tested in the first report of the Aeon scope, but I included it for continuity). The scope used in today’s report is different, so we will see whether that makes a difference to the results.

I had no intention of conducting this test, but then reader Silver Eagle asked this:

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.

The last test

I had thought about that when I conducted the last test and noticed that my groups were larger and smaller depending on the air pressure in the gun when I started shooting. I mentioned that in the report, and Silver Eagle caught it. So what he asked was the same thing I also wondered — if there was no change that resulted from the gun, what would the groups do when the scope’s magnification was changed? Granted I’m using a different variable scope for today’s test, but if this phenomenon is common to all variables, we should still see it.

TX200 Mark III Tom bench
This time I shot my TX200 Mark III.

This will be the last time I conduct this test. It’s not that I have proven or disproven anything conclusively. In fact, just the opposite. I have opened a can of worms and they are scattering everywhere! There are so many variables here that I don’t have enough time left on earth to test them all. But I wanted to see what kind of results I got from a different kind of airgun and a different scope under similar test conditions.

TX200

Silver Eagle suggested the test. Why not shoot my TX200 Mark III at 50 yards and see whether changing the power on its variable scope changes the POI? The rifle is currently scoped with the 4.5-14X42 Sidewinder Tactical scope that I have found to be one of the finest riflescopes I have ever used. While it doesn’t have the magnification of the Aeon 8-32 AO scope with trajectory reticle that I tested before, this scope is astonishingly clear. It should be able to perform this test at 50 yards on much lower power.

I chose to shoot at 6 power and at 14 power. That should be enough separation to show a POI change if there is going to be one. For my pellet I selected the Crosman Premier 7.9-grain dome because this rifle likes it a lot. When I first shot the rifle on this day, the impact point of this pellet was about 2 inches low. An adjustment raised the POI into the bullseye. The rifle was fired with the stock rested directly on a sandbag, as that has proven to be the most accurate way to test this airgun.

First group at 14X

The first official group was fired with the scope set at 14 power. The wind was dead calm throughout the test, so conditions were ideal. On this first scope setting, 10 pellets went into 1.519-inches at 50 yards. The group is centered on the bull and is fairly round. This will be our baseline.

TX200 Mark III Premiers 14X
Ten 7.9-grain Crosman Premier pellets landed in 1.519-inches at 50 yards when the scope was set on 14 power.

Second group at 6X

Next I adjusted the scope back to 6 power. The parallax appeared perfect, but at 6 power it’s impossible to know for certain at 50 yards. I shot another 10-shot group. These pellets went into 1.073-inches. The group is still well-centered, but the center of the group did drop by about 1/8-inch. That’s definite movement, but not enough to be concerned about.

TX200 Mark III Premiers 6X
Ten 7.9-grain Crosman Premier pellets landed in 1.073-inches at 50 yards when the scope was set on 6 power. The center of this group is in the same place left and right, but about 1/8-inch lower than the last group.

We learn two important things from this second group. First, there is a slight but definite shift in the center of the group. It’s not large, but it’s there. That addresses the question of whether the POI shifts when the magnification is changed. We have now seen it on all three of my tests with a pellet rifle at 50 yards, plus I told you about a much larger shift at 200 yards that my buddy Otho experienced.

The second thing we see is that the rifle grouped better with the scope set on lower power than when it was set on high. If you recall, I did a test of that phenomenon for you in response to the question posed by our Moscow correspondent, duskwight. Duskwight also showed that in his guest blog that was in response to the test I conducted a week earlier.

I don’t think the scope’s magnification has much to do with the group size. What I think is that as long as the image in the scope is clear you can do just as well with it set on low power as when it is set on high. And that’s exactly what I did next.

Third group at 14X

For the third group I adjusted the scope back to 14X. That should tell us two things. First, does the group shift back to where it was initially with the scope set at 14X, and second, is this group larger or smaller than the one shot on 6X?

This time 10 pellets went into a group measuring 0.916-inches between centers at 50 yards. So this group is a little smaller than the last group that was shot at 6X. But notice that the POI shifted back up again. Perhaps it isn’t in exactly the same place as the center of the first group, but it’s easy to see that it is higher than the group shot at 6X.

TX200 Mark III Premiers 14X 2
Ten 7.9-grain Crosman Premier pellets landed in 0.916-inches at 50 yards when the scope was set on 14 power. The center of this group went back up to almost where it was the first time I shot at 14X.

The final group at 6X

Now I adjusted the scope back to 6X to shoot the final group. Will the center of the group drop back down again?

This time 10 pellets went into 1.295-inches. And the center of the group definitely dropped below the enter of the last group. It’s even a little below that last group shot on 6X.

TX200 Mark III Premiers 6X 2
Ten 7.9-grain Crosman Premier pellets landed in 1.295-inches at 50 yards when the scope was set on 6 power. The center of this group dropped even lower than where it had been at 6X the first time.

Conclusions

There are several conclusions we can draw from today’s results. First, there seems to be no question that the POI does shift when a variable power scope’s power is changed. I believe this differs from scope to scope. Some scopes will shift more than others. I recommend that you test your variable scopes this way on every airgun you own and see what results you get.

Next, I think this test demonstrates once more that the power of the scope has very little to do with how accurately you can shoot with it. While I was conducting this test I was also testing a Remington 788 30-30 rifle at 200 yards. I have a Leupold M8 4-power scope on that rifle, yet I was able to see the crosshairs against the black bullseye clearly at that distance. Optical clarity is the most important thing in a scope, I think.

TX200 Mark III 30-30 200 yards
Six 30-30 bullets went into 4.559-inches at 200 yards when fired from a Remington 788 that was scoped with a 4-power scope. Any one of these is a kill shot on a deer at that range.

Finally I was surprised to see my TX200 Mark III do better at 50 yards than my Talon SS. That Talon SS has long been my go-to air rifle when the ultimate in accuracy is required. This test taught me that the TX is another solid performer. I’m not saying the TX is more accurate than the Talon SS, because I don’t think it is. But for today’s test it was the ideal gun to use.

Summary

As I said at the start of this report, this is the last test I will do specifically on this question. Of course I will remember these results in all my future shooting, as I hope you will. This lesson is too hard-won to forget. Test your scopes under the conditions you intend using them, and remember their results. That should make you a more confident shooter, and confidence builds skill.

89 thoughts on “POI shift when changing the scope’s power


  1. BB– Long before this report I made a discovery and a decision. Most of my air rifles wore large variable scopes. I used the higher powers when testing pellets using supports. When I shot these rifles at paper targets, offhand and other positions, I used the lowest power. I did the same thing when plinking at plastic medicine bottles, and orange juice bottle caps. I was handicapped by the large mass of these scopes. I tried using a low power (2,5x 20) scope that I bought at a club flea market. To my surprise, groups fired from a rest were almost as tight as those from the same rifle at 10-14 x. Of course , the rifle was much better balanced for position shooting. I am now replacing many of my variable scopes with 2.5 x scopes. I have used some of these scopes on my .22 cal. rifles, from 50′ to 100 yards. Parallax at this low power is not a problem, down to 10 yards.I am using these scopes on co2 powered rifles, and on low powered springers. And these scopes cost.$20–, new. I could go on, but my cat, Wrecks, Is demanding that I feed him his 11 o,clock bedtime snack, and it is now 12.38.. Ed


  2. B.B.

    This report comes just at the right time for me. As I mentioned I just purchased a Diana 34P and the only scope I had on hand that was not mounted was the RWS 3-9×44 AO Night Pro that was bundled with my 460 Magnum. Using an RWS Lock Down mount to compensate for the droop the gun is shooting 1/2″ groups at 25 yards. I was going to order a “better scope” translation a 4-12 or 4-16 something but after reading today’s blog I don’t think a different scope will really make much improvement in my groups with this rifle. I think just maybe 1/2″ groups with a .22 caliber 34P are quite acceptable, I’ll save my money and spend it on something else.

    David


    • Sounds good to me! I used to get frustrated when I couldn’t get tight groups like my .177 guns can shoot outta my 392 but if you think about it like 1/2″ is only 2 pellets abreast things come more into perspective.


    • Pa.oldman,

      I can say that after shooting 2 springers, both .22, both at 7 mag.,….a 1/2″ group (of 10), is “quite acceptable” in my book as well. One max’s at 10 power and the other at 12. I would love to be able to shoot with something that would go into the high 20’s or even the low 30’s,….just to get that more exact, close-up picture. My steady would not allow that though.

      With winter around the corner, I will be doing 5 shot groups indoors at 41′ at max 10 and 12 mags. Hopefully by spring, my steady will have seen improvement. In other words, I want that movement to be at it’s worst and most exaggerated in an effort to better control it.

      As new airgunner, I am amazed at how even the (slightest mistake) will throw a shot. Getting a nice 1/2″ group going at 25/30yds. and have a shot or two land a 1/4″-1/2″ out, is quite frustrating.


      • Chris,
        My springers are my least favorite guns; both are VERY hold sensitive and require constant intense concentration to shoot well. some springers, like the TX200, are much less sensitive.


        • HiveSeeker,

          I got lucky with this 34P it is shooting at about 13 ft lbs out of the box. Much less hold sensitive then my 460 Magnum. Specs claim 800 ft/sec if you assume this is with light weight lead pellets this should be more like a 16 ft lb gun. The gun is very calm almost like it has been tuned. Maybe since I shoot only springers I am more used to them but even the 460 Magnum while hold sensitive does not require what I would term “intense concentration” to shoot well. I can’t bag rest my guns like B.B does the TX, but I don’t find the artillery hold all that difficult now that I have become practiced in it. But the take away for me from today’s blog is not how well B.B. can shoot a springer at 50 yds but that he did not need to crank up the power on his excelent scope to do so. The RWS 3-9×44 I am using on my 34P is not in the same class as the Hawk he is using but it is as sharp at 9X as the Leapers scopes in my collection so no need to spend money on a new scope cause I ain’t gonna shoot the 34P any better with at 12X or 16x then at 9X.

          David


          • David
            With you on the magnification and shooting on lower power.

            And there is something else that happens that people don’t seem to say anything about. At lower magnification you have more feild of veiw. In other words you can see more of your shooting area.

            I know it don’t mean much if your shooting at a paper target. But if your shooting at pests it allows you to see more of the area around your pest.

            Like say if I got my scope on 6 magnification I can see a 30 foot area. And if I go up to 16 magnification I can only see 12 foot of the are through my scope. And those are just examples of what I see through the scope. But it represents what happens at the different magnifications when I look through the scope.

            I was talking the other day on the blog that it might just be better to get a fixed lower magnification scope and without parallax adjustment. That way you eliminate the variables in the scope. But the main thing would be to choose the right parallax for the distance your shooting your air gun at. I found I can get away with a 50 yard parralax scope because of the lower 6 magnification I shoot at. In other words I can still see the target clear at 50 to 70 yards out and all the way back into about 20 yards. Maybe really even as close as 16 yards.

            But the reason that does work for me is because that is the distances I shoot at all the time.

            Now if somebody was shooting out to 40 yards and in I would try to find maybe a 30 yard parralax scope that was like a 4 magnification. That scope would probably still show a target clearly at 10 yards out to 40 yards. But after 40 yards the target would not be focused as clear. And the lower 4 magnification is what helps keep the scope in focus at those distances.

            But yep got to research what charectrics a scope has and know what your going to use it for before you buy one.


            • With you on that, Gunfun. Walking around, I found it hard to find the target quickly when the scope was on high power. But for the 50 yard shots on starlings, the higher power setting was a help, as you could better place the shot where you wanted it. I may have to repeat BB’s test on my own guns, in our “indoor” range here at work, just to see what the effect is and how much. That last paragraph in the blog pretty much says it – if you don’t test it you don’t know for sure.

              BTW, I put a reply in the H+N pellet blog on our hunting trip last weekend, don’t know if you saw it. 2 deer on Saturday afternoon, home and meat in the freezer on Sunday night. A good trip. The deer were thicker than fleas over there. So were the turkeys, but neither of us had a tag. I don’t think it’s legal in our state to take them with an air rifle (we didn’t have those along either), which is a shame, because it would have been easy 30 yd. shots.


              • Ben
                What’s up. And no I didn’t see your hunting results. If you want to reply about something that was talked about in a previous blog just post like you did today. Or if it is specific to the topic and your adding results and talking with a certain person then just reply under that person’s comment. That way they will receive a email and will know to comment back to you.

                But sounds like a good trip you had. And the turkey are everywhere out by me. Thought about hunting again but just don’t really feel like bothering the nature or wild life anymore. I actually just like watching the wildlife anymore. But don’t get me wrong I have nothing against hunting and done my fair share throughout time. So mostly plinking and target shooting and an occasional pest here or there.

                And lucky you a indoor range at work. Well you know what the next question is. Where do you work that would have a indoor range?


                • Aha, yes, I think I replied to one of my posts. I’ll get this figgered out someday.

                  I’ve never hunted turkey, they aren’t native here, but there have been a lot of efforts to transplant them, apparently successfully, over the last decade or so.

                  My “indoor range” is just a clear lane down the shop (we have a new building that is about 120 yds long), I taped it out and marked the floor discreetly – could get a 100 yard shot in if I shoot through a couple of doorways. So, if I come in on the weekends when nobody else is around, it’s do-able. I do have to be careful about pellet splats flying around and landing in the boss’ inventory, which is why I bought one of the Champion pellet traps that BB recommended awhile back. It still flings a few pellet scraps, though, so now I’m trying to figure out how to fabricate a snail trap.


                  • Ben
                    I have thought about making a snail trap myself.

                    Probably wouldn’t be to hard. A fairly thick plate of steel and a pipe cut in half and welded to the top and bottom of the plate. Then maybe some half inch diameter steel rods welded to the top and bottom pipe half. Set the plate at about a 20 degree angle before welding the bars on the side. Oh and make the steel rods longer than your plate so you can drive it in the ground. Well that’s what I would do because I would be using it outside in the dirt.

                    That bottom pipe that’s cut in half should collect all the lead. And if you made the plate heavy enough you could probably even use a firearm with it.

                    But yep one would be nice. And if somebody started making them I bet they would sell.


                    • GF,

                      Yeah, that sounds like what I was thinking, but maybe two plates, one entering the pipe at a tangent, and the other set about 20-40 degrees from the first plate. Couple of end caps. The whole thing could be set so the pipe is vertical, and the spent pellets would drop into one of the pipe caps.

                      I also think, with a bit of tooling investment, that the entire “snail” could be made from one sheet of steel, and then the end caps/plates welded on.



              • When I received my 392 in trade for a lawnmower it was totally wrapped in camp duct tape and dressed out like a full fledged Turkey gun so maybe they’re legal to take with airguns somewhere. I’m still holding out for Texas to legalize a few things but my patience is starting to wear thin.


                • Reb,

                  Up here we legalize marijuana, but there are efforts afoot to ban all lead ammunition due to concerns about affects on people’s health. Thus, wanting to be extra careful if I use our shop as an indoor range and not leave a bunch of lead dust/scraps lying around.


            • Gunfun,

              Interesting comment about pesting. One reason for getting this new rifle was pest control. Setting the scope at a lower power definitely makes it easier to find your target and I will be dialing back the power when I use the 34P for pesting. Unlike my Benji Trail NP this new gun is accurate and will do much better both for paper punching and pest control then the Benji. I am going to test the combo to see if there is any change in the POI when I dial back the power. So yeah this is a very timely topic for me, thanks B.B. you have giving me something to both work on and think about. Good job yet again.

              David


              • David
                How is that 34p doing? Do you like the shot cycle; how about power and accuracy? Is yours a .22?

                That 46e under lever should be here anyday. I believe somebody said it has the 34p power plant but I may have that confused with another gun. So that’s why I was just asking the questions about yours.

                And yep its much easier to keep a eye on what’s going on in your feild of veiw when you use the lower magnification.


                • Gunfun,

                  The 34P is a .22 caliber. Not sure if my rifle is typical as it is only shooting at a little over 13 ft lbs, it is my understanding that the 34 power plant is a 16 ft lb power plant. A call to Pyramyd Air tech support has me comfortable that my rifle is not defective so I’m keeping this one. That said my rifle has a very smooth shot cycle with no trace of the honk I have heard plague some 34s. It cocks almost as smoothly as the NP Trail. The T06 trigger breaks crisply at 1.5 lbs. And my gun is accurate, repeatable groups in the 1/2″ range @ 25 yards with 15.89 gr. JSB Diabolo Exact Jumbo and 14.5 gr RWS Superdomes so far, still have some other pellets I want to try.
                  Your gun probably will have the T05 trigger like my 460 Magnum which is also a very nice trigger. I am interested in learning more when you get this 46e.

                  David


                  • David
                    Good to know. And I know I have had good luck with the JSB 15.89’s in my . 22 airguns.

                    Hope the 46 likes them. Going to find out tomorrow. Put my Hawk half mildot scope on it today before leaving for work. Only had enough time for about 5 quick shots to see what it felt like. So far I like it but won’t know the real story till I get some time on it.

                    I’ll post some results as I go.


        • HiveSeeker,

          Got one of those and a LGU, both in .22. Both seem pretty forgiving. When the groups grow, it’s usally me messing up. Still new and still learning the finer points. Chris




  3. Hi folks,

    This is an important test (and must have been a lot of work, so let’s thank BB for that). Still I find the shift in POI pretty subtle. This, together with the expanding and shrinking groups *might* indicate that further testing might be a good idea. So, maybe some other folks might want to run some tests of their own.

    I can’t really because a) I’m not a good enough shot and b) I only have 10, maybe 11 meters of distance which is fun, but totally insufficient for this test.

    There’s one other thing I’ve been wondering about… My cheap Leader 4×32 scope shook loose its objective lens and I had to screw it back in. I noticed that I can use it to adjust the “focus” or sharpness of the image. If I adjust it for maximum sharpness at the range I’m shooting at, will this work somewhat like a parallax adjustment or am I on the wrong track here?
    I have to say, for a € 40 scope, this thing isn’t half bad and so far the Diana 31 hasn’t killed it 🙂
    The Nikko 3-9×42 that I have on the FWB300S is a *lot* better though, but also twice as expensive.

    Stephan


    • Stephan,

      I think one lesson I learned is that some scopes shift more than others. The Hawke I used for this test was subtle, but I have seen vintage Weaver scopes that shifted by many inches.

      Like I said in the conclusions of the report, I think it’s a scope by scope problem that each shooter needs to figure out for their own gun/scope combination.

      B.B.



  4. I have bought some field target to use at home to practice shooting at to simulate the kill zones we use at my FT club and our smallest kill zone is 1/2″ so that is the size of the kill zone I am using in the three FT targets I have purchased and had to have washers welded into two of them as they are the cheap Crosman squirrel shaped resettable Ft targets from Wally World that come with an 1 1/2″ kill zone which is 1/4″ larger than our largest kill zone. The third one has exchangeable washers to be able to vary the kill zone size to your liking and it has the 1/2′ kill zone washer installed.

    I have them at 25 to 35 yards which is my maximum distance in my backyard so that if I can hit those 1/2″ kill zones with receptiveness at the distances they are at to allow me to have a much easier time hitting the larger ones on our FT course. We do have two 1/2″ kill zone FT targets out at 50 yards as well but I do not have that distance to shoot at in the backyard so I make do with what I have but I will say that I can hit those kill zones at least 8 out of every 10 shots with my 177 Mrod being closer to 10 out of 10 and then my FWB 300s, B40, FWB 124, RWS 48 and then the cheap Crosman spring/NP guns at the very bottom.

    It has helped me improve my scores in my FT matches every time I shoot the first Saturday of the month as I started at a score of 7/44 in my first match with a cheap Crosman clone spring gun and then was given a deal on my 177 Mrod Gen1 that has allowed me to improve my score each successive match until my last match was a 30/44 and November will be one year of shooting in FT every month so I feel I have made quite good progress in a short time frame.

    BD


  5. I shoot at the maximum allowable power setting for hunter class which is 12 power so my scopes are never changed from that power level and all my sight in is at 12 power so while I am aware of the POI change with changing the power setting it does not affect me as all I use is 12 power exclusively since my eyesight does not allow for me to see well enough at lower power settings.

    BD


  6. BB–Re your comment that ” the power of the scope has little you to do with how accurately you can shoot with it”. The sniper rifles of WW1 and 2 had low power scopes ( by modern standards). They were very effective ( especially the Russians) with those scopes. Hiveseeker— tell your cat that my cats are well cared for. Ed



  7. Howdy Mr. BB, Very cool to see you & what you were shooting. Ad a scope level & make it wrong handed & that’s my exact setup as per your recommendations. Could not be happier. Ya dun me good! Thanx again, sir.
    Shoot/ride safe.
    Beaz


  8. Anybody heard of a Daisy no. 102 model 66? It’s all gummed up inside right now but it says Plymouth Mich. I just never seen this variant , it has an ornate metal lever and two hole in the right side of the receiver. I have to wait about a week before I can place my order without draining my account.


  9. B.B.
    Very informative! Well what did we learn, “Second focal plane scopes are inaccurate at variable magnification”. Does this mean that you need to re-sight in whenever you change magnification levels? Are first focal plane scopes more accurate(they sure are MUCH more expensive)? Are fixed magnification scopes more accurate?

    Interesting report, but what does it all mean?
    Thanks,
    -Yogi


  10. B.B.,
    Thanks for another great report. One more thing to remember when out hunting.
    Noticed recently that Hatsan is now making underlevers with gas pistons. Any chance you reviewing one of these for us?
    I am tempted to sell my TF87 and buy a Hatsan.

    Pete


  11. B.B.

    Thanks for the real world testing. I can see you were a little frustrated. We sure do appreciate all the shooting you do to answer our questions. I kind of stirred up the hornets nest with my non shooting scope tests. I try to give a full honest reply on the blog. I do not want to step on any toes here. I think my results with the three scopes I tested earlier are still good. My theory on setting up the scopes was not so good. But I have learned a lot and have more confidence in what is happening between the gun and scope and target. I just received a crony and plan on doing some more tuning on my .22 Marauder. I know my tests are not always conventional but that is when I seem to learn the most.

    Thanks again for all the work you do on this blog. I have been reading it for a long time and have just recently started to participate. I enjoy the everyone’s feedback.

    Benji-Don


    • Benji
      I believe that all info is good. Every person will take something different from the info received.

      And I don’t think you stirred up a hornets nest. You were just communicating what you experienced.

      If a person does a test; say what it is. Why does somebody think it stirs something up when its just conversation about what was done. Or if somebody has other ways of doing something. It’s just more information to learn from.

      Post what you have to say. I’m sure people are listening.



  12. Thanks for the test. Sorry to open up the can of worms any bigger than it was! LOL
    Will remember to keep the magnification set the same on the scopes I use.
    Looks like dialing them down for a better field of view and then dialing back up for precision is not such a good idea!



      • It’s not that bad, if you wanna take shots on high power just sight it in on high and remember to take your shots on high or at least know what the difference in impact is on whatever power you do use.


      • Good question. Usually I adjust them up for precision (mostly bench shooting.) In the field, that would be a big toss up. Probably will have to pick a place in the middle and just stay there. After finding the new POI!
        This kinda reminds me of the people that insist on tapping the turrets after adjusting a scope to “set” the new settings. Guess older scopes needed that final tap to set them. Makes one wonder if there is a good procedure on adjustable mag and parallax scopes to help the POI stay consistent. It really stinks to fire off an excellent group that is way off the POI.


        • Silver Eagle,

          One upside,…you do not “blow out” your POA. 😉

          Have done that most of the summer testing pellets. Your POI can always be adjusted. Getting those super tight groups are another story all together. Chris


        • SE
          That was a good answer I would say. Pick a place in the middle.

          I think a person should try different magnifications and see what works for them.

          And I don’t tap the scope after adjustment. But I have found that I should take a few shots before I make another adjustment on the scope. So maybe that would fall into that category of letting the scope settle. And maybe that is something also to look for when you try out a new scope. Maybe it doesn’t need that on evry brand scope a person trys.

          And with you on the POI being off from the POA. When I shoot I want to take one shot at every target and hit a given kill zone if you will call it that. I’m not even worried about the group size when I shoot.



  13. Chris U, “should get better,…quicker”! Mama tried, Doc’s told her that often when I wuz younger. Never happened, so she just tried ta convince me I wuz adopted after bein’ raised by wolves.
    Beaz


  14. I would like to make a request for a review of the U.S. Marshals Commemorative Peacemaker.

    I was fortunate enough to be able to get one, but have seen no follow ups on it. It is a beautiful piece for a great cause, however, I found the ‘weathering’ finish leaved a bit to be desired.

    There have been some really nice ‘weathered” releases to date but it seems, in my mind, Umarex just didn’t get this one quite right. Might be because they took an existing production revolver and tried to ‘modify’ it. Seems they scratched the weathering on and did a job that really doesn’t reflect a holstered piece.

    I’m proud to have it though and have the 2015 US Mint US Marshals Service 225th Anniversary silver dollar to match. Only wished they had got the finish a bit better, on the revolver that is. The coin is flawless.


    • Krimson,

      Welcome to the blog. I have the gun you mention, plus an engraved single action that was offered through Pyramyd Air.

      The performance of these revolvers is identical to the standard Single Action Army, which I did cover quite well here:

      /blog/2015/07/colt-single-action-army-bb-gun-part-4/

      But I do have a new BB to test, so maybe I can work the Marshal’s revolver into that.

      B.B.


      • Hello B.B.
        Thanks for the reply, sorry to take so long to get back but I’ve been up to Maine visiting my daughter and her family. The highlite there is my 16month old grand daughter. Life couldn’t be better for sure.

        I’ve seen your review on the SAA and got a silver one right off the bat. A fine piece. I’m also expecting FEDEX to deliver an engraved silver one tomorrow. Seriously looking forward to that.!!

        Thing with the Marshals is the way it’s been finished off. Seems to me it would have been just as nice if they hadn’t gone to the trouble…

        My son-in-law and I had a ton of fun shooting spinner targets with my Beretta Cx4 w/ red dot. Almost too much fun. I most always drag something up to shoot.

        Looking forward to what you and others might have to say on the Marshals.


  15. B.B., Sorry that I can’t seem to find the time to read your blog everyday, at preset, but I got all caught up with this piece and will make my final comments here too. First, I missed a question from a previous blog:

    >I was hoping CalinB would chime in, because he si the one who
    >put me onto this. It’s a misalignment of some sort, no doubt, but with optics,>
    >even microns matter.

    Scope focus and zoom adjustments work by moving a lens element fore and aft along the scope’s optic axis. It’s a tough mechanical challenge to move a scope lens fore and aft without cocking it with respect to that axis. Like you said, microns matter! Also, if the lens rotates as it moves fore and aft, then the lens must also be perfectly aligned with the optic axis of the scope in the first place, or the image it produces will move off-axis with the lens rotation. Finally, the spherical geometry of the lens (they are spherical lenses) must be nearly perfect, i.e. the optical path length across the lens surface must vary only with radial distance from the center of the lens. However, I suspect that the tilting and alignment challenge is the more significant one.

    By the way, in engineering grad school at U.C., Davis, I worked on the DSP (digital signal processing) software that was used to correct the images produced by the Hubble space telescope. My Masters degree thesis was titled, “A Microcomputer-Based Controller For A Liquid Crystal Lens.” I did my research in a lab with a door that automatically locked whenever we powered-up our powerful gas lasers. As a backup, we also posted a sign on the outside of the door: “Caution–Do not look at LASER with remaining good eye!” 😉

    >I have opened a can of worms and they are scattering
    >everywhere! There are so many variables here that I don’t
    >have enough time left on earth to test them all.

    Yes. You’ve identified a problem, but because of all the variables, you might be able to replicate the results of any given test one day but not the next. Nonetheless, these errors are part of your overall “error budget” and they do affect your average accuracy level. I’ve made my case here for the benefits of using some kind of optical apparatus or non-live fire method for testing scopes. That’s what the manufacturers do. (They can’t very well mount and shoot every scope to evaluate it!) My Zero-Point is a satisfactory optical tool for this purpose and I have no doubt that it has enabled me to shoot accurately more than any other method that I might adopt to evaluate scopes, but not everyone here sees its value over just shooting (or similar non-live fire methods, apparently) and I’m done with discussing the Zero-Point here.

    I’d like to reiterate that I’ve tested dozens of scopes across a $100 to $6000 price range and the magnification zoom control is not, in general, the worst mechanical offender when it comes to maintaining a zero. The worst offenders are parallax adjusters, with the rotating objective “AO” style being the worst system in terms of both the magnitude and the nature of the optical errors it creates.


    • calinb I tried to reply to your comment above but it looks like I just made a general post so if you look at the bottom of the comments you will see my question. Thanks


  16. I have a fairly new TX200 and recently purchased a Leapers 3-9 x40 true hunter scope. ( Nice stuff! ) My POI moves too, consistently. At times a good 1″ almost 2″. This led me to believe that I should site in the combo using the 9x say at 40yds. This way any target closer using a lower power should hit target. Am I correct?

    40 yds is about my max safe distance in my back yard. I’m also new to the sport at this level, the TX200 and Leapers scopes. I’ve had a Gamo 440 for 10 years but only pulled it out few times a year.



    • My TX (or me ) does the same thing, driving me crazy, not to mention going broke buying every gismo & pellet going. I am shooting with a Hawke Airmax 30 scope 6x24x50. 1/2in.10 shot groups @38yds. (1 out of 8 or 10 targets). If you figure it out PLEASE let me know. thanks good luck…


  17. I think I am in experiencing and AO problem where changing AO changes point of impact. I noticed a lateral point of impact change when shooting from 10 yards and then changing to 50 yards (actual distance to Target.) This happened to be the new utg 3-12 X32 bugbuster with side wheel adjustment. My other scope which is a 3 by 9 X32 bugbuster has the AO on the bell. My results with that scope are much better. I can hit the same Target at 10 yards or 50 yards with just a vertical poi change as would be expected. I decided to try a different test. I shot at 10 yards every time. Every shot that was focused for 10 yards was hitting the Aim Point. Every shot that was focused for about 50 yards gave me a blurry Target that I could still see, but the poi moved laterally to the same side every time.

    I think the scope has a problem. What do you think?


    • John

      Unfortunately, scopes do not work as perfectly as we would expect them to .
      Temperature changes move the POI and focus. If you adjust the AO, they often change poi. Clicks do not always correspond to POI movement.
      How much does it take to be acceptable or not ? If you were hunting deer (or larger) would it matter ? Bug shooting would be a different story.
      FT shooters use cheat sheets for anything that affects POI .
      How bad is it ? This is something that you should expect, but can be grateful for if it is acceptable.

      tt


      • thanks for your reply. It’s bad enough that when it first happened I went “what the heck?” When I could repeat the problem I knew it wasn’t a flyer. my other scope which is a 3-9 X32 Bugbuster works fine. I think I’ll keep using it and let other people be the guinea pig on the new 3-12.


    • Your method is similar to the one that led to my discovery of this common and significant problem. (Obviously the significance depends on both its severity and your accuracy needs). I was shooting a very accurate Savage 17HMR between 25 and 100 yards when I first noticed a significant and repeatable group POI shift, back and forth, every time I adjusted my AO.

      Make sure that you keep your eye perfectly centered on the eyepiece while testing to eliminate parallax error at the “mis-adjusted” setting (where you also must live with a slightly fuzzy image, which doesn’t usually impact accuracy significantly if holding on the center of a black bullseye). You can also increase the depth of field of your scope by selecting a lower power level, if it is a “zoom” scope, and reduce the fuzziness. Most people don’t need as much magnification as they typically prefer to use to shoot accurately.

      I have tested several dozens of scopes and, though adjuster-induced POI error is most prevalent in AO models, a side adjuster parallax / focus mechanism, as you have, can also suffer from the problem. If you goal is sub-MOA (or even sub 2-MOA) accuracy, this problem is common and a significant hindrance to accuracy goals in low to mid-priced scopes of all makes and models. As a Vortex Optics technical rep at SHOT show once agreed with me, you pretty much have to test and hand-picks scopes in the low to mid price ranges to avoid the problem…either that or don’t trust your zero every time you adjust the parallax focus! Though the problem is uncommon is high-end scopes, I have still found it on a $5500 Schmidt-Bender model that is popular with (wealthy ;)) air gunners!


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