This is a Daniel Defense DDM4 A1 chambered in 5.56 with 16 barrel. Comes with one 30 round magazine. This is in excellent condition. Mounting System Picatinny Caliber 5.56mm NATO Muzzle Thread 1 ⁄ 2 × 28 TPI (Threads Per Inch) Gas System Carbine Barrel Length 14.5" Barrel Profile M4 Length 31 1/2” – 34 ¾”