BR-99 12-gauge semi-automatic shotgun is designed like an AR-style rifle with similar controls. The shotgun has a 3-inch chamber and a 20-inch barrel that accepts choke tubes. It features a 5+1 or 10+1 capacity detachable magazine. The gas piston operating system takes low- and high-pressure loads. The stock, pistol grip, and handguard are made of polymer, and a rubber recoil pad and rubber cheekpiece on the buttstock offer increased shooter comfort. Rails are built into the handguard to mount optics or laser sights.