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 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.

Olympic made OA93 rifles with folding stocks too and I think you can still buy the upper and stock from them.

Stokes had a like new one for sale a year or so ago with folding stock.

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