Details
Bulldozer w-SBA3 Brace 5-Inch 1-16 .45 ACP AR-45 Freefloat M-LOK Pistol Full Build Kit
This is an AR-45 pistol full build kit chambered in .45 ACP, centered on a 5-inch slim profile 4150 CrMoV steel barrel with a Parkerized finish, a 1-16 twist rate, and a 37-64x28 thread pitch specific to the .45 ACP bore diameter. The AR-15 billet upper receiver for pistol calibers anchors the front end with a design purpose-built for the pistol caliber AR platform. The 4-inch Ace Series freefloat M-LOK handguard wraps the barrel along the forend and keeps the front end compact and clean on this pistol-length build. A PCC AR bolt assembly for .45 ACP and an M4 Mil-Spec charging handle complete the upper side. The lower completion package covers the full internal lower component group, a Mil-Spec heavy-duty 6-position buffer tube, an AR-15 9mm carbine buffer, a standard carbine recoil spring made in the USA, and a full rear hardware group. An SB Tactical SBA3 adjustable pistol stabilizing brace in black closes out the rear end. Everything above the lower receiver is addressed in one kit. Lower receiver not included.
Key Features
- .45 ACP chambering, 5-inch slim profile 4150 CrMoV steel barrel, Parkerized finish
- 1-16 twist rate, 37-64x28 thread pitch
- AR-15 billet upper receiver for pistol calibers
- 4-inch Ace Series freefloat M-LOK handguard
- PCC AR bolt assembly for .45 ACP
- AR-15 M4 Mil-Spec charging handle
- Complete Mil-Spec AR-15 lower parts kit
- Mil-Spec heavy-duty AR-15 6-position buffer tube
- AR-15 9mm carbine buffer
- Standard AR-15 carbine recoil spring, made in the USA
- AR-15 M16 Mil-Spec receiver end plate
- AR-15 carbine castle nut
- SB Tactical SBA3 adjustable pistol stabilizing brace, black
- AR-15 .45 ACP Birdcage muzzle brake, manganese phosphate finish, 37-64x28 thread pitch
- Black 5-8-inch crush washer
Perfect For
- AR-45 pistol builders who need everything above the lower receiver for a compact .45 ACP build
- Shooters pairing this kit with an existing AR-45 lower receiver
- Builders who want a platform-specific bolt assembly and a complete pistol component set with the SBA3 brace included in one kit
Upper Assembly
The AR-15 billet upper receiver for pistol calibers is the correct upper receiver choice for the AR-45 platform, designed around the dimensional requirements of pistol caliber operation that differ from a standard AR-15 upper receiver. The 5-inch slim profile 4150 CrMoV steel barrel brings a Parkerized finish and a 1-16 twist rate to the .45 ACP chamber, threaded at 37-64x28, a thread pitch specific to the .45 ACP bore diameter. The slim profile keeps the front end lean and well-suited to the compact pistol-length layout of this build. The 4-inch Ace Series freefloat M-LOK handguard wraps the barrel from the upper receiver along the forend, keeping the overall front end compact and purposeful with M-LOK slots along the handguard body for accessory attachment.
Bolt Assembly and Charging Handle
The included PCC AR bolt assembly is specific to the .45 ACP chambering and is the correct bolt choice for this platform. A standard AR-15 bolt carrier group is not compatible with the .45 ACP AR-45 platform, and this bolt assembly addresses that platform-specific requirement directly. The M4 Mil-Spec charging handle pairs with the bolt assembly inside the upper receiver to complete the upper interior and finish the front end of the build.
Lower Completion Components
The complete Mil-Spec AR-15 lower parts kit covers the full internal lower component group, including the fire control group, magazine catch, bolt catch, and all associated pins and springs. The Mil-Spec heavy-duty 6-position buffer tube, AR-15 9mm carbine buffer, and standard AR-15 carbine recoil spring made in the USA form the buffer system at the rear of the lower, matched to the pistol platform and the blowback operation of the .45 ACP AR-45 build. The AR-15 M16 Mil-Spec receiver end plate and AR-15 carbine castle nut lock the buffer tube down at the rear of the lower receiver. The SB Tactical SBA3 adjustable pistol stabilizing brace in black fits over the Mil-Spec 6-position buffer tube and closes out the rear end of the build with an adjustable length of pull and a well-regarded brace design trusted across the AR pistol platform.
Muzzle Device
The AR-15 .45 ACP Birdcage muzzle brake with a manganese phosphate finish threads onto the 37-64x28 muzzle end of the barrel, a thread pitch and caliber designation specific to the .45 ACP bore diameter. The included black 5-8-inch crush washer seats at the barrel shoulder and completes the muzzle hardware for this kit. The .45 ACP specific Birdcage muzzle brake is the correct muzzle device choice for this bore diameter and thread pitch combination.
Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. Lower receiver not included.
