Introduced 2017. Chambered in 5.56/.223, .300 BLK, and .450 BM. Includes rifle-length AAC SquareDrop handguard, allowing fast, solid attachment of accessories at seven different angles. Mission First Tactical Minimalist Stock, 16-in. 1:8 4150 lightweight contour barrel with Melonite (FNC) finish. A3 flattop upper receiver, AAC 51T flash hider, ALG Defense Advanced Combat Trigger, Mission First Tactical grip and magazine. Weight, 6.0 lbs for 5.56. Overall length, 35 in. Price shown for model 91056 in 5.56/16 in. M-Lok variants available in 5.56 (90178) with a 1:8 twist rate and 300 BLK (90179) with a 1:9 twist rate.