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SPR A5M XP Rail: Nonstandard?

2308 Views 12 Replies 7 Participants Last post by  BlackNoSugar
Moved the scope from my AR-15 to the XP last night just to see what I would see. The scope is mounted to Burris extra high QD rings, so I expected it to be suboptimal, but I did not expect what I found. The rings lock up tight on the rail on the LMT MRP (receiver and rail all one piece) but they wiggle laterally on the XP. A lot. Adjusting the rings did not help.

These rings are too tall for the XP, and QD is not all that useful, so I'm not greatly concerned that this ring/scope combination does not work, but I am puzzled that the XP's rail does not seem to be standard.

Any thoughts? What rings are you using?
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Badger Ordnance standard height .823" rings. There is some forward and back adjustment room until the nuts are tightened. There is no lateral (side to side) movement once tightened. I tried these rings on both the A5M XP rail and on a separate Badger Ordnance rail that I originally purchased for my Rem 700. Movement on both rails is the same forward and back but no lateral once the rings are tightened.

I did not measure the rails but the both appear visually to be cut to the same specifications.
I had been running my Knights Armament 30mm one piece mount with not problem till I picked up the rings I finally settled on for my A5M.
I now have TPS TRS #30580 low .925" rings TSR 30mm low 7075 Aluminum - TPS Products
They fit great, tighten up tight, and zero issues out of them, haven't run into a problem with the factory rail on the A5M.
Funny how Badger Ordnance says .823" is standard while KA says that .925" is low......

And they wonder why we have a hard time figuring out the stuff.
Don't some ring manufacturer's measure from the middle of the ring while others measure from the bottom as well?
Even so, if you measure from the middle of the rings vs the bottom, the difference on a 30 mm tube is 15mm or 1.5cm with is almost 2/3 of an inch. The difference between .823 and .925 is about .1 inch which is much smaller than 1.5cm or 2/3 of an inch.

And if you measure from the bottom of the mount to the middle of the ring or bottom of the ring, you still wind up with all sorts of differences that do not match.

Does one measure from the bottom of the rail mount or the top of the rail mount to the center of the ring or the bottom of the ring or to the top of the ring, internal or external. This is what I mean by confusing and no standard to scope ring heights.

Further, are the different measurements from individual scope ring mounts vs uni mounts?

And what about the ones that are listed as low, medium, or high, or extra high and provide no measurements....

I am just saying that this is all very confusing when hunting for rings and making a determination what to use as one makers standard ring height may not be another makers standard ring height due to measurement differences and measurement points.

I only relate this because I had a hell of a time deciding on what rings and what height they needed to be for my glass and mount option for both the A5M XP and the Rem 700, one with an integral rail and the other without one.
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