SRC is proud to offer this outstanding Complete AR-15 Upper Assembly chambered in the potent 25-45 Sharps that comes fully assembled and ready to drop onto any standard AR-15 lower receiver. This upper includes a 416R stainless steel SRC Precision Barrel featuring polygonal 1 in 10 inch twist rifling, M4 feed ramps and 5/8 inch - 24 muzzle threads. Additional features include 25-45 Sharps laser engraved ejection port door cover and our patent pending Relia-Bolt and Balanced Bolt Carrier assembly.