The 57 Center AR57 Upper is a blowback operated upper chambered for the very mild recoiling 5.7X28 mm FN ammunition. This unit works with a unique, low-profile 50 round magazine which can be purchased separately. The magazine sits on top of the receiver and barrel making for a very compact unit. Ejection is straight down through the mag well, falling at your feet for easy clearance after a shooting session. Blowback operation is simple and reliable with only the bolt reciprocating. The whole 5.7 upper is very rigid with a monolithic machined 7075 T6 aluminum receiver and hanguard unit offering almost three feet of MIL-STD 1913 Picatinny rail and offering perfect alignment of optics. Ventilation is enabled by multiple holes in the handguard. The barrel is a free-floating 4140 chrome-moly steel, 16″ unit with a unique multi-port flash hider. The AR57 AR15 upper comes with a dedicated recoil buffer specific to the 5.7X28 mm ammunition which fits into the receiver extension of an M4 type telescopic stock. The AR57 AR upper is 25″ (63.5cm) O.A.L. and weighs 4 lbs, 9 oz.
Check the price of the AR57 upper at Brownells, a name you can trust.
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