AR-57 5.7x28mm Semi-Auto Upper Rifle
$699.00The AR-57 is a unique straight-blowback semi-automatic upper receiver that fits any standard AR-15 lower and accepts FN P90 magazines, giving shooters 50 rounds of 5.7x28mm in a familiar AR platform. Cases eject downward through the empty magwell, keeping the shooter clean and the action reliable. A