Scope Checker from rail parts

[dskogman]

I thought I'd try to put together a scope checker from off the shelf AR rail components to see if it would work. I ended up using more parts than I thought, around $50 in all :

1. Dual Rail 45/90 Degree Picatinny Scope Riser Mount
2. Two 45 deg Offset Side Rail
3. Low profile Picatinny Riser Mount

The weather was hot, humid and windy so the mirage made any precision impossible. I couldn't tell if the scopes were off or not after a shot but they did not appear to. I'll have to wait till October I guess before I can get any decent conditions

At any rate the 45 deg tilt makes for a compact and pretty light mount. Took a little getting used to adjusting the turrets but not difficult. Getting to the offside scope is a little awkward. Not as good as a custom mount but OK if you don't have one.

 

[Geronimo Jim]

Well I'll be damn!

 

[Bart B.]

Im curious as to how much zero changes for one scope by itself with the offset one removed to when both are installed. The extra mass offset from the complete rifle's center of mass will change the muzzle axis direction when bullets leave. It may be only 1/4 MOA.

 

[dmoran]

Im curious as to how much zero changes for one scope by itself with the offset one removed to when both are installed. The extra mass offset from the complete rifle's center of mass will change the muzzle axis direction when bullets leave. It may be only 1/4 MOA.

It very well indeed could change the MOA capability of the rifle/load as well as normal Zero placement of the load, as could any mass change. The amount of mass would dictate the amounts. But all that is a hypothetical to the topic, that would have no effect on scope checking for reticle shift where POA is all that matters, and don't understand the questions relevance.
Donovan

 

[Bart B.]

It depends on how tests are conducted.

What's the details? Objectives, conditions and standards.

Will the reference scope have zero reticle shift?

 

[swd]

Since it's all AR parts, mount that sucker up on my 50 Beowulf. That'll give it good jolt! lol

 

[dmoran]

@Bart B.
With all the resent discussion, details, and results on the topic, would think you'd grasp it better then you must. Suggest you read those threads more in detail, and forget all about what the rifle/load is doing. Reticle movement from rifle fire is what the scope checkers being discussed are being used and built for.
Donovan

 

[dkhunt14]

The only thing I might question is the stresses and vibrations on the scope the same with them mounted at an angle. Most times i see the vertical up and down part of the scopes fail. Now that is is on an angle I think it would change how the forces act on it. Matt

 

[Bart B.]

Reticle movement from rifle fire is what the scope checkers being discussed are being used and built for.

So it is OK if both scopes have reticle shift from recoil?

 

[dmoran]

"Scope checkers" have prevailed to simulate culprit scopes to shift and proven scopes to hold. Which to me proves them to be reconstructive, factual, and test worthy.

@dskogman pieced together a checker from rail parts, and was kind enough to share it here. Will be great to read his results and how it works out for a checker.

If someone has a better way, by all means share it and the results of its reproduction of POI shifting with known culprit scopes. If it can't reproduce POI shifting to a known culprit, then it isn't an adequate instrument or test.
Donovan

 

[mysticplayer]

That is an awfully "gansta" set up

Question... with all those parts bolted together, are the bits and pieces going to move under recoil? I am just wondering since most of the AR bits are designed for holding objects of little mass, would hold a 2.5lbs object cause shifting?

If it doesn't matter if the checking scope is not in the same plane as the scope being tested, could you bolt a rail to the side of a stock, put on some rings and mount the checking scope that way?

It would be below the scope in question but level and looking in the same direction.

Would that work????

Jerry

 

[dskogman]

It locks up pretty good but obviously not as good as solid mount. Mounting on the side of the stock would introduce more potential for movement. Maybe if it was an aluminum stock it would be ok.

 

[Ned Ludd]

I've been waiting for someone to try something like this ever since the scope checker thread(s) came out. Strength and stability are key, if this setup has those, it will work. Kudos to you dskogman on your ingenuity!

 

[Dgd6mm]

How much in parts?

 

[dskogman]

$50