Tag Archives: ps90 ar5

AR Five Seven (AR-57): 50-Shot 5.7x28mm AR-15 Carbine

By David Crane defrev at gmail dot com August 11, 2008 An outfit called 57 Center is making an interesting patent-pending 5.7x28mm upper receiver for AR-15/M16 lower receivers called the AR Five Seven (AR-57) that utilizes 50-round FN P90/PS90 PDW magazines. The magazines are top-loaded and horizontal-mounted, just like on the P90/PS90. It would appear that that an emptied-out standard …

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