Tested 13 Scopes

I recommend doing this with a 338 only if you have an action with an integral Picatinny rail. While I've never heard of it happening, I would be concerned with shear loads on the screws & pins that hold a bolt-on rail to the receiver. Two scopes, two sets of rings/ mounts, plus the checker can be a lot of force!

 

Would you give us a heads up on the Leupold when it returns, Please!
Thanks for your time!
Pete

 

Muzzle brakes break scopes. Mike.

 

I won’t test scopes again until next winter. So the Leupold will go on the shelf once repaired for 11-12 months

 

why

 

Concussion, I agree with him.

 

OK, Thanks!

 

Hmm. I don’t doubt that muzzle breaks are hard on scopes. But look at all the 375-416 shooters in the ELR crowd running the NF Atacr, Beast, Etc. I have heard reports of Leupold VX series having issues with larger magnums and poi shift.

 

I will choose to disagree.
in open air, not an issue IMHO
under a low ceiling, may have some affect, but breaking a scope..i just do not see it.

 

Proof?

 

Nope, forget it. Brakes are fine. Mike

 

I have made a scope move by shooting a .44 mag next to it. Concussion is hard on scopes. Worse than recoil in my opinion. I think the aggressive brakes are harder on scopes than the recoil itself. The only high end scope I have seen actually break, as in reticle laying in the bottom of the scope was on a 6 dasher heavy gun with a brake, almost zero recoil, lots of muzzle blast though. If Im using an aggressive brake with rearward angled ports, I want a good scope, integral rail, and good rings, especially on a magnum. I have shook loose rails and rings, even pinned rails when using those brakes. No problems without a brake or will less effective designs.

 

I always wonder when I read of these scope tests, is the first shot movement the scope's fault, and could any fixed procedure used before and during testing help to determine this?

After a long career in mechanical engineering and lots of testing of products and designs, I have observed that test equipment, and equipment under test (EUT), may need a couple cycles to "settle in". Erroneous data on the first cycle is not uncommon because of fixture or EUT initial movement. This was particularly true in testing load cells which measure movements much smaller than these scope movements.

For scopes, which in general, have a screw to push the internal tube, and a spring to move it the opposite direction, are likely to have some hysteresis. In addition, like any screw advanced device, always moving it in a direction where the screw advances the adjustment is a requirement for accurate data. For example, machinists will always approach a cut from the same direction, backing off a couple turns, then advancing inward to the setpoint.

I could imagine that a scope, after installation on the fixture, having the turrets cycled from full up and full right ( maximum spring assisted movement) to full down and full left, then back to full up and right, then to the zero point. After which, all adjustments are made in the positive "screw in" direction, and if required to go "screw out", it be screwed out 1 full turn, then screwed in to the setpoint each time.

As far as movement on the first shot, I myself cannot fully assume it is the scope adjustments that are moving. It could be a "settling in" of the fixture and the mounts. Perhaps a couple shots should be made before data recording starts. Movement after this point is definitely erroneous.

For those who say "when I step up to the line, the scope had better hold whatever adjustments I input, including the first shot", I agree with you. Once mounted, and fired a few times, you must depend on the scopes repeatability.

Please do not take this post as a complaint about the testing, it is just my mental rambling on the concept of "move on the first shot and it fails". Also please note that JET did NOT say, "move on the first shot and it fails", I postulated that concept. JET simply posted the data, and explained his actions in post #6. He did state the one scope that moved multiple times was going back to the manufacturer.

I am NOT disparaging the testing done by JET, and I recognize his EXTENSIVE experience in correlating his test data to his competitive shooting experience. He knows when a scope is not to be trusted. We should all thank him for his efforts, and for publishing his data.

 

I think most of us do overlook a small first shot shift, if the scope is solid after that. However one scope model went 10 in a row with no first shot shift. I do not think the mount or rings are shifting. One thing I do find interesting is how some do not consider this test worthy. However holding a scope by hand in a collimator is. Think about this, .0001" shift at a ring is about 1/16 moa on target. Theres more than .0001" in the surface finish on a scope tube that touches those v blocks, hold a part in your hand and it will grow a .0001".

 

Powderbrake

All very good and valid comments. I did not state it when I wrote this up but prior to testing the scopes I mount two frozen scopes on the F&C Scope Checker to validate the mount, rings, and scopes themselves. Guess I should have stated that up front. In previous tests I believe I stated this in the intro. When I did this there was absolutely no movement.

Could there still be issues? Certainly. When a scope moves once I don't worry to much about it and that scope will not be used on a #1 or #2 rifle I plan on shooting. When a scope moves more than once then stops or does not stop moving during a test I always remove it, test another scope or two then try it again to see if it will repeat.

Good Shooting

Rich

 

I never understood the notion that some scopes “settle” after one or more shots. This indicates it only stops moving for some period of time before it starts to move again. So how long or how many shots do you think it holds before you need to fire those settling shots again?

 

Rich:
Thank you for the information on your reasons to select or reject a scope. It is not necessary to outline all your steps of the test, you served the purpose by publishing the data.

Jerry

 

I think most people are referring to settling shots after windage &/or elevation adjustments are made. If the reticle moves on say, the 10th shot, after not moving on shots 2 thru 9, you've got a problem. I haven't seen that, but I suppose it's possible.

Remember, when checking scopes for POA stability under recoil, you must often make large adjustments before the first shot to make the scopes point at the same spot. You may also find scopes that don't require "settling shots" when dialing up or to the right, but do when dialing down or to the left. Learn your equipment, so to speak.

 

Jet - just out of curiosity, had the scopes that "moved" on the first shot but were subsequently found to be "solid" been fired previously since the scopes were mounted?

I can easily imagine that some movement might be expected on the first shot or two if a scope had been removed and remounted. However, if the rifle had already been fired after the scope was originally mounted, then movement of the reticle, even on the first shot only, still seems somewhat problematic.

Along the same line, my understanding is that it's not a bad idea before shooting to twirl the elevation and windage turrets well past the intended set point to "unload" the erector spring and make sure the erector assembly has moved to [at least] the desired set point, and only then tighten the turret back down to the desired set point. Basically, the idea is to partially unload the spring then tighten the spring loading back down to the desired setting, as @powderbrake mentioned.

Have you ever used this sort of an approach when testing scopes? If so, did it have a noticeable impact on reticle movement during the first shot or two?

Thanks.

 

For me, scopes being tested are not removed from their rings - they are tested as they sit on my rifles. True, I have to remove the entire assembly off the pic rail and move them to the test rifle. I torque them down to the test pic rail as I normally would when moving scopes between match rifles.

I try to simulate a BR match sight in period when testing.

1. make large elevation/windage adjustments (full range up/down/L/R) and then bring my POA to test point
2. Test
3. make small elevation adjustments up
4. Test
5. make small elevation adjustments down
6. Test
7. Repeat small windage adjustments left and right only
8. Test
9. make small random elevation/windage adjustments
10. Test