The Brownells BRN-180S in 5.45x39mm is a short-stroke piston AR-15 upper paired with a standard lower, accepting AK-74 magazines through Brownells' compatible lower receiver. It ports the BRN-180 piston operating system to the Soviet caliber for shooters who want AR ergonomics with AK-74 ammunition. Type: Rifle Action: Semi-Automatic Caliber: 5.45x39mm Capacity: 30 Year introduced: 2021, USA Weight: 80 oz Overall length: 34" Status: Active Intended use: Recreation, Hunting, Multi-Caliber