Springfield armory and few others manufacture side screw mount, which is expensive and after several shots, it can become loose. In the military, most of side mounts with the screw were crimped and welded for the stability. Other option is to place directly on top of the receiver (attached to stripper clip guide), but this will require minimum work done to the gun (if you are handy enough, this can be done easily). A.R.M.S. and few others also make this mount.