Caliber: .300 AAC Blackout. Capacity: AR-15-pattern magazines. Barrel: 16 in., Criterion 1:8 twist, stainless-nitride finish, A2 flash hider, .625 in. diameter. Upper/Lower Receivers: Forged 7075 aluminum, M16/M4 specs. Stock: Magpul CTR buttstock. Grip: Magpul MOE. Sights: Optics-ready top rail, laser engraved T-marks. Weight: 6.2 lbs. for MI-FC300CRM12. Trigger: NA. Overall Length: NA. Features: MI-CRM Combat series handguards, M-LOK compatible. Hard-coat anodized Mil 8625 Type 3, Class 2 finish, M4 feed ramps, .250-in. takedown pins, M16 bolt carrier group. Works with standard AR-15 components and magazines, receiver rear takedown pin detent hole threaded for a 4-40 set screw. Models denote handguard lengths.