I put my 511 as far forward as I could on the receiver’s rail without having the movable claw portion of the EOTech mount bridge the gap between receiver and rail. Now I wonder if it’s too far forward because the other (fixed) side of the EOTech mount bridges the gap and contacts the rail.
Am I OK like this, or should I move it further back?
I wouldn’t bridge the gap, as that’s pretty much asking for trouble. The two pieces can potentially move in opposite directions, so bridging can be problematic. For the most part, there is no reason to do it. Having the front overhang the receiver is generally okay, as there is sufficient clearance under the EO to not create stress.
Of course, having owned several EOTechs now, I no longer use them, either.
YMMV
So in this case, where the clamping portion of the mount is entirely on the receiver I’m probably OK?
Yes. So long as the clamp and bracket are entirely on the receiver, and are nowhere fixed onto the handguard, you should be able to avoid twisting issues.
The unspoken rule is that the optic does not get mounted or bridged to the handguards. This was a huge issue with the two piece rails that were not free floated. They had a tendency to shift ever so slightly affecting POI.
Not so much an issue now with the improved FF rails but still not a good idea IMHO.
Also forgot to mention that the Larue EOthingy mount will push it forward while still keeping it mounted to the receiver.
And Larue mounts are bomb-proof.
I guess my concern is that while the clamping portion of the mount is completely on the receiver, the left side rail extends over the rail. I don’t know how much contact it is making, though - I may try and sneak a feeler gauge up there to see.
I’m considering a riser anyways, so this may be moot.