Scopes FYI

Get or give advice on equipment, reloading and other technical issues.

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AlanF
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Joined: Wed Jun 15, 2005 8:22 pm
Location: Maffra, Vic

Re: Scopes FYI

#16 Postby AlanF » Fri May 19, 2017 9:54 pm

Wal86 wrote:AlanF

Ive been thinking about your testing, and I was wondering what your comparing against.. As your results maybe conflicting against one scope to another...
"Immediately after the first shot complete disagreement between 3 scopes"
I may be wrong and not exactly understand your testing but without a fixed scope (neutral) how can you get accurate results..

One way too check a rifle scope for repeatability is put a collimator on the end of your barrel and adjust your focus and rear parallax, scopes that are shifting point of impact will shift with this test...


Alan


Alan,

I have a platform that will take up to 4 scopes side by side. This time I only used 3 scopes, because from past experience with my scopes, I hadn't seen any disagreement of more than 0.15 MOA. What I need to have is at least two scopes that agree very well, and that will make any others that don't agree suspect. After the first shot no two scopes agreed, so only one (or none) stayed put, and I had no way of knowing which one. For my next test I'll use 4 scopes, and won't include the Sightron, because it seems to have a problem. With 4 scopes there is a better chance of at least two of them agreeing. The "frozen" scope used in the US tests makes things simpler, but would you be 100% sure that it doesn't move? Also it means wrecking a scope. I actually bought the Weaver T24 purposely for the tester, because they have a reputation for reliable mechanicals, but at least it can be used for other things.

The aim of this testing is to see if the POA moves between shots because of recoil. The collimator would detect changes because of focus, power etc. adjustments, but I think the grid idea works better in this case.

Alan F

Wal86
Posts: 132
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Location: Kilmore, VIC

Re: Scopes FYI

#17 Postby Wal86 » Fri May 19, 2017 10:29 pm

AlanF

Well I hope I'm not wrecking a scope cause im getting one frozen and going to try out a full mechanical mount system, :lol:

Alan

Brad Y
Posts: 1991
Joined: Fri Jun 26, 2009 8:21 pm

Re: Scopes FYI

#18 Postby Brad Y » Sat May 20, 2017 12:20 am

Alan I was just doing a bit more reading on accurate shooter and came across another thread on exercising the turrets of a scope. Wonder if you try that maybe your scope might come good again?

KHGS
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Joined: Thu Oct 20, 2005 12:46 am
Location: Cowra NSW
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Re: Scopes FYI

#19 Postby KHGS » Sat May 20, 2017 9:12 am

I do not profess to be a scope expert in any way, but I have always followed an "ease springs" procedure with my target scopes. Much of what goes on inside scopes is to do with spring tension, so it seems elementary to me to preserve spring tension & prevent spring "set", think about that. In any case I do not seem to have settling issues with my scopes. Maybe what I do works, or maybe I have been lucky!
Keith H.

DaveMc
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Joined: Mon Aug 22, 2011 6:33 pm

Re: Scopes FYI

#20 Postby DaveMc » Sun May 21, 2017 8:40 am

It was a very shocking thread no doubt. Not being able to cross check any of the findings we cannot count or discount the thread but rather I would like to say: TREAT THE RESULTS WITH CARE - not gospel and not necessarily incorrect either. - rather just worthy of further examination and testing. I would dearly love to have a couple of his "failed scopes"

AS Peter has said, I have tested quite a few scopes on the "recoil simulator" or "whackometer" (Alan this is a collimator that has a removable plate that ois on "linear bearings" of a type such that it returns to a fixed point very reliably and consistantly (cannot visably measure/see any differences in max zoom (55 -60 power which you can detect around 2 sec of arc movement) and seen no errors of this magnitude with any comp scope. In fact I would go as far as saying I have not been able to get any visible errors in recoil simulation, zoom or focus shift I have certainly failed a couple of other scopes and found errors in my mounts.

This is not to say it didn't happen - just the difference in our results to his would warant further exaination between the two test methods and various cross checks.

The mount issue is a real one and I want everyone to be particularly careful hanging multiple scopes off ally rails for testing under recoil - especially if they are only held down with 6-48 screws (not in this posters case I believe but other possible errors). Errors I have seen in mounts may surprise you (They surprised me. Especially one particular scope where I had been through and tested 6 others, tested this one and showed massive movement (1/2 minute). I remounted and got similar. These were originally quality steel mounts, lapped and mounted to the scope on a quality rail (then transferred to the test rail).Then as a matter of trial - changed mounts to a single piece SPUR and 99% of movement disappeared.

Mounts interacting with rails, interacting with receivers and interacting with scope tubes can all be a possible cause for error and maybe one that is far more prevalent than we give credit to (I know Stuart Elliott would go to this first). Certainly a lot of problematic scopes that came to us showed no errors under a rigorous testing program when remounted on our machine and similar at NF test facility (and yes they do let me know when there is an error) and March who now have a drop/recoil tester too.....

So where do we go from here ------ More testing :)

Wal86
Posts: 132
Joined: Sun Nov 20, 2016 5:10 pm
Location: Kilmore, VIC

Re: Scopes FYI

#21 Postby Wal86 » Sun May 21, 2017 9:29 am

Dave Mc

I understand that your "recoil simulator" is a collimator, but i can see inaccurate results being measured when you take in all the variables:
(mounting of scope, four scopes on a mount fixed to an action cant give correct measurements, there would be flex there 100%, especially under heavy recoil. This does not simulate correct mounting of a scope.Also which scope is the neutral, therefore you get conflicting results etc..

A fixed collimator will show scope errors 100%.. scopes shouldn't move point of aim from a power or focal shift.

The other test I do is put the suspect scope on a known rifle that shoots in the low .1s or under and go and shoot a group in perfect conditions.. Then put known scope back on rifle and shoot a group, If there is anything wrong with the suspect scope it gets found out...

Cheers

Alan

AlanF
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Joined: Wed Jun 15, 2005 8:22 pm
Location: Maffra, Vic

Re: Scopes FYI

#22 Postby AlanF » Sun May 21, 2017 10:09 am

Yes, more testing I agree. My approach will be statistical. Scopes can be swapped between the 4 rails, rings swapped between scopes etc. and patterns will emerge. If the mounts are moving, this will show it.

Matt P
Posts: 1270
Joined: Mon Nov 14, 2005 8:22 pm

Re: Scopes FYI

#23 Postby Matt P » Tue Jun 13, 2017 8:22 am

Hi All
Some more testing by the original author see here http://forum.accurateshooter.com/thread ... t-36999392

Matt P


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