at the rear of the mount there is a little room "for windage". I call it slop. If overtighten it prevents the bolt from operating smoothly or non operating at all. Simple fix is two plastic washer to take up the slop so that the it can be tighten properly. Finger tight allows for it to become loose after firing 5 rounds. I fabicating the two washers and it works great!!
Pros: Cheap, easy installation.
Cons: Should have tighter tolerances.
This review was written in the old system and had content requirements that are different than reviews written today.