He thanks for the look, is it normal for a ARMS 22M68 to be able to move to the front and rear. I noticed it when it was adjusting my scope caps on my Aimpoint. I have a KAC SR15 M4 with 22M68 ARMS cantilever and M2 aimpoint rig. It dose take good pressure to do it but should I be able to move it? Any way to stope the movement? Is it a problem?

should be no movement at all.  When mine did move, it was because I didn't torque the allen screws on the scope ring enough.  Also make sure the locking tab (helps to look at it from below-looking up at it)is is positioned correctly and wedges the rail on your upper.  Sounds like it wasn't secured properly!  Hope it didn't fall off. Hope this helps too.
[img]http://www.imagestation.com/picture/sraid80/p960dfaf7b48261681b9178c7ac892124/fb0967f5.jpg[/img]

Thanks for responding. No it is loose from the ring mount and the flat top rail. I did get all of the SLP cleaned off and it seems to hold a little better. Any thing else I can do to make it hold better?

They should only move if a great amount of pressure is used. When you put any ring on a rail, you need to push it forward brgore locking a lever or thumb nut in position. All mounts want to go forward when the weapon is fired, so thats why you push it there before you go shooting.
It sounds like you don't have any problem since it doesn't move easily. If it moved easily, them I'd suspect that you had an undersise non mil spec rail, but not in this case.
Good shootin, Jack