Originally Posted by
bb223
And I have tightened it very securely.
QED, if it's moving, no you haven't. That's not a bust to your chops, that's just logic.
As F2S stated, use a tool to take it past hand-tight, just don't go crazy with that.
The step immediately prior to tightening, the application of forward pressure, is the step missed most often, and it applies to anything that's gonna get zeroed.
If that device isn't pressed toward the muzzle before tightening, there will be a gap between the rear of the rail slot on the receiver and the forward edge of the recoil lug on the rail interface of the device. Imagine that gap, imagine the direction of the recoil impulse, then think to yourself: "How does a jackhammer work?" Instead of one great big shot, it used LOTS of little tiny ones to bust through concrete. That's what recoil impulse can be like, over time; lots of little hits that can loosen up what you've zeroed, certainly shifting your zero and maybe even shaking the thing up to the point that it falls off the weapon. Don't laugh, it's happened!
If you have left room to move, it will move over time, period. So, push to the muzzle before tightening so that there is no room to move, then tighten. Whether your carry handle is perfectly flush with the front of the receiver is irrelevant, so long as the rail interfaces mate up with the rails correctly.
Contractor scum, PM Infantry Weapons
Bookmarks