is there any other ar15 type uppers out there that have a recoil buffer built in the upper (or anywhere else other than in the stock)other than the z-m and oly's oa93 pistol? and where could i find blueprints of the oly pistol or the z-m configuration. also, if anyone has one of these for sale, i would be interested in hearing from you. i am a machinist, and was thinking of building a new type of upper, relocating the buffer assembly, so any info would be appreciated. thanks p.s.
iwould be interested in ar180 blueprints too.