TacFire PK300LPK10: TacFire\'s AR-300 Unassembled pistol build kit includes a black parkerized barrel with a 1:8 twist rate, 5/8x24 spiral fluted Krink style frowarder muzzle device; a Slim M-Lok free-float handguard; 7075-T6 billet aluminum stripped upper; 5.56 bolt carrier group; Mil-Spec charging handle, dust cover, forward assist, heavy buffer, pistol length gas tube, low profile gas block; complete pistol buffer tube and lower parts kits all made in the USA. This model has a 10.5\" barrel and 10\" handguard.