Eotech sliding on rail

[Cookie91/38]

Hey guys,

I have a question regarding my eotech 512 moving on my rail. This is about the 4th time Ive gone shooting, followed all the proper steps to tightening eotech(loctite,torque,push forward on rail etc), and after about 20 rounds it has slid back on the rail. The weird thing though is that the optic is still very tight to the rail, but has moved back. I though optics tend to move forward hence why I push it forward against the rail. Any ideas on why its doing that? If its still tight and doesn't wiggle at all, should I just leave it? Thanks in advance, Evan

[Vinz]

what type of rail do you have?
its not a used 512 is it. The sides might be bent or worn.

[Cookie91/38]

Sorry, it's just an ar receiver picattiny. And no it was new.

[Cookie91/38]

Any ideas?

[Munny$hot]

Google picatinny 1913 dimension and meassure the thickness of your rail with a caliper. Your rail is probably out of spec causing your eotech to slide around.

[RobG]

The pic rail has to be out of spec. The Eotech runs a screw that fits into the rail opening. I cannot see how it could slide and if so, it couldn't be more than thousandths of an inch. Here is a pic I found...http://i181.photobucket.com/albums/x...h512Bottom.jpg

Does yours not look like that?

[Cookie91/38]

The pic rail has to be out of spec. The Eotech runs a screw that fits into the rail opening. I cannot see how it could slide and if so, it couldn't be more than thousandths of an inch. Here is a pic I found...http://i181.photobucket.com/albums/x...h512Bottom.jpg

Does yours not look like that?

Yes I do have the screw going through, when I say it moves I mean when I push it forward in the little slot, by the time Im done shooting, it has been pushed back to contact the back bump in the rail if that makes since. Which is only a couple thousands of an inch.

[OpticsPlanet]

The 512 comes with two screws... one is a thumbscrew with a slot, the other is a hex-head that sits flush. I would recommend using the hex head, and using a torque screwdriver.

If I recall correctly, EOTech says it should be tightened to 17 inch lbs.

See if a buddy has one of these you can borrow:

http://www.opticsplanet.com/wheeler-fat-wrench-with-10-bit-set-553556.html

Mark H.

Mark H.

[strongpoint]

Eotech sliding on rail

The GG&G Accucam add-on offers a different way to torque down the side clamps. It might be overkill for solving this problem (sounds like all it needs is some more torque applied to the cross bolt), but it's a nice piece of gear.

[Cookie91/38]

Ive heard tightening too much can cause it to come loose easier than if set at 17lbs. Is this true? Cause I really torqued it down

[Cookie91/38]

If my rail is out of spec, what do I do? Buy a new upper receiver? Or should I trade for an aim point

[Munny$hot]

Ive heard tightening too much can cause it to come loose easier than if set at 17lbs. Is this true? Cause I really torqued it down

Usually if you applied to much torque you could shear off the bolt head or strip the retention screw.

If my rail is out of spec, what do I do? Buy a new upper receiver? Or should I trade for an aim point

Was it a complete/stripped upper, what brand is it, was it new or a blem?

[HK Dave]

Google picatinny 1913 dimension and meassure the thickness of your rail with a caliper. Your rail is probably out of spec causing your eotech to slide around.

This would be my guess as well.

I once had an Aimpoint CompM4 that wouldn't tighten down on a Spikes Tactical upper receiver. Turns out the receiver was out of spec.

Simple solution was to change the mount to an ADM at the time.

Too bad that can't be don't with an Eotech 512.

[sammass]

The rail spec issue came up in talking with LaRue C.S. regarding the OEM Ruger GSR rail. That rail has the bars milled down to the support blocks just on the outside to lighten the overall weight. LaRue advised there may be scant material to clamp their mount to and it may batter the surface, making it easier to slide. All that said, I wonder if the rail material - aluminum, alloy, steel - might be the culprit as the mount is shaving the grip surface of the mount. Was the receiver made of 6066, 7075 T6, or some other soft variation? Is it screwed on or cast in to the upper? Pretty sure it is not steel if cast. Is the rail softer material than the mount? Or the inverse?