Rifle Scopes Scope checker

[memilanuk]

I'm curious... I've seen a few threads on people making jigs/fixtures to hold scopes for testing tracking while off the rifle. Heard @Lowlight mention something along those lines in a podcast. I'm seeing people talking about whether the scope tracks... but not so much about whether the optic actually *holds* point of aim?

There was a long (50+ page) thread over on AccurateShooter.com where some of the guys involved in LR BR and F-class started trying to debug why some scopes seemed to 'group' better than others, even for 'identical' models.

Granted, these are much 'lighter' scopes than many of what you see in the tactical/practical arena - say what you want about BR/F-class, but they actually have weight limits. No 30# .308s!

As a result, some of the 'high end' optics are a bit more 'delicate'. What they ended up doing was rather than statically checking the scopes *tracking*, they set up a scope mount so that two scopes could be mounted side by side on the same gun, marry up the point of aim, and then fire the gun and return it to the original point of aim - and see if one of the scopes isn't pointing where it should. The results were surprising!

Sadly, the thread got pulled because 50+ pages is too much for most people to bother with, so they'd just skip to the end - and ask the same question(s) that had already been answered a half dozen times. The raw data, luckily, got saved and reposted - sans all the B.S. and comments - over here.

There is a place (Field & Cave Outfitters) making the scope checker mounts now, and there is another thread here showing some of the 'uses' for them - including checking tracking

Figured as much $$$ as some folks have tied up in their high-end glass that someone might be interested in checking more than just tracking...

 

[Vitali1342]

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[Rthur]

Killswitchengage did many of these.

R

 

[memilanuk]

The static base for testing the tracking on one scope at a time, or a side-by-side mount for testing scopes holding POA under recoil?

 

[spife7980]

Killswitchengage did many of these.

R

Not like he’s talking about. Killswitch placed it in a static mount and checked how accurate the clicks were in its range of travel.
This guy is talking about actually holding zero.

One scope is frozen so it’s always pointing the same (literally non adjustable frozen). Then you align the second scope to that same point of aim. Fire a shot and see if your scope is still pointed at the same exact point as the frozen scope.

Lots of scopes would shift a tenth of an inch for the first or second shot and settle in, some were perfect, some were just awful. The point was to check your equipment and not just take the fact that it cost 2k bucks for granted.

It does require scopes with magnifications over 30x though they said to be able to tell so it’s defiantly into the weeds for what most of us are after, practical accuracy that you can carry around without a cart. But in benchrest where your groups are measured in the thousandths of an inch instead of the tenths that the little bit of shift can make or break your winning group.

 

[memilanuk]

@spife7980 having your scopes POI move during a string the way some of those did will drive you f'ing insane during 1k F-class as well - you start questioning your load, your barrel, your position. For a lot of the positional stuff, that little bit of movement of the scope reticle might well be negligible in the bigger scheme of things.

I agree that a lot of the tac/prac scopes are probably just under the magnification range where you can really start seeing this sort of thing. But if I was dropping the coin for say, a NF 7-35x ATACR... I know I'd be putting that sucker on a scope checker.

 

[Lowlight]

Our jig can do both, test tracking and return to zero, although the return to zero will require extra effort to repeat the process.

The trick is weight, and mounting of the fixture, our jig is 30LBS to minimize movement, the Kill Switch Humble was the same, very, very heavy I beam to prevent movement in the system.

It's necessary, we sent them all to the various military schoolhouses for them to use too. here is the USMC schoolhouse mounting their NF scopes with it

 

[Rthur]

The static base for testing the tracking on one scope at a time, or a side-by-side mount for testing scopes holding POA under recoil?

Tracking on a fixture.
Return to zero position after dialing ect.

R

 

[memilanuk]

Understood. That's really just a secondary feature of the scope checker mount that I linked to. The real goal is holding POA shot to shot to a desired level of precision.

 

[memilanuk]

This is the kind of thing they're trying to find (and avoid!):

(excerpt from the raw data file linked to in the first post)

 

[Lowlight]

This is the kind of thing they're trying to find (and avoid!):

(excerpt from the raw data file linked to in the first post)

I have a question about that raw data,

Can you mount the scope as normal and does it group better when shooting it minus the fixture. I can see if you have unexplained fliers in something that should not be, but with a system that like with moving parts is that fixture bouncing and causing the shift. what is the baseline for movement?

If I can take a tested scope that is labeled junk and then you can go and shoot a .25 MOA group, is that scope really doing something wrong?


We went to our fixture because we found too much movement in just the rifle scope combo, how are these rifles being locked in place by the shooter when test firing.

Millet had videos on their machine which tests this, but it's all done in the fixture. No external influence

 

[memilanuk]

It may not be something that transfers well to different setups.

This image is from an old (Hood) scope checker, made back when 1"tubes and front AO were the norm. Little tight for modern 30+ mm tubes with side focus.