I remember seeing One Shot Tactical had a few in...They are okay for tightening up the play between receivers but they actually can cause more ware on your rifle apparently, don't quote me on that though...
completely agree. As long as the optic doesn't move in relation to the barrel and the said barrel is not disturbed you're good to go.If welding an upper to lower results in zero improvement in accuracy, jamming anything between the receiver's is probably not going to make much of a difference.
Anyone has any experience of having one installed on theirs?
Anyone knows where I could get one here in Canada?



























