GENESIS ARMS Gen 12 SBM 10.5" Barrel 5rd Shotgun Chamber 2 3/4" and 3" 12 gauge shells Muzzle Thread: 1.375X24 Blast Can with Crown Muzzle Device Short Recoil: The barrel reciprocates reward as the shot leaves the muzzle, creating the energy to cycle the weapon system; This means there is no gas system to foul up, and no tuning, making it self-regulating Free float handguard with M-LOK rail at 3, 6, 9 o'clock and full picatinny top rail Right side charging knob; GEN1 DPMS 308 patterned lower Mil-spec buffer tube; 308 short carbine buffer 3.8oz Round Receiver Extension (aka, buffer tube); Hogue rubberized grip; Hiperfire trigger (3.5lb-4.5lb) Includes: 5-round magazine, Soft case, Limited warranty