TacFire 7.5" Unassembled AR 300 Blackout Pistol Build Kit with Lower Parts Kit

The TacFire 7.5" Unassembled AR 300 Blackout Pistol Build Kit with Lower Parts Kit delivers a precision platform for building a short-barrel rifle system optimized for subsonic ammunition and sound suppression applications. This unassembled kit includes all critical components needed for a complete pistol-length AR build in the increasingly popular .300 Blackout cartridge.

The kit features a parkerized steel barrel with 1:7 twist rate—optimal for stabilizing both subsonic and supersonic .300 Blackout projectiles—paired with a 5/8x24 Krink-style spiral fluted muzzle device for convenient suppressor mounting. The 7075-T6 billet aluminum stripped upper receiver provides rigidity and durability, while the slim M-Lok free-float handguard eliminates barrel contact for consistent accuracy. Component selection includes a 5.56 bolt carrier group, mil-spec charging handle, dust cover, forward assist, heavy buffer tube, low-profile gas block, and pistol-length gas tube. The complete lower parts kit and black A2 pistol grip round out the assembly. All major components are manufactured in the USA.

This build kit suits operators and enthusiasts building a dedicated .300 Blackout pistol for reduced sound signature work, specialized training, or subsonic ammunition platforms where bolt carrier cycling reliability is non-negotiable. The 7.5" barrel length and pistol configuration provide a compact profile while maintaining functional velocity with subsonic rounds when paired with a suppressor. Builders experienced with AR platform assembly will find all necessary components included; unassembled kits require proper tools, headspace gauging equipment, and technical knowledge to complete safely.

.300 Blackout has gained adoption among tactical professionals, hunters using subsonic ammunition, and AR platform builders seeking a versatile intermediate cartridge. The 1:7 twist rate and Krink-style muzzle device reflect purpose-built engineering for suppressed shooting and specialized ammunition performance in a compact platform.