The TacFire BU45ACP4 .45 ACP 4" Complete Upper is a compact pistol-caliber AR-15 upper built around a 4-inch black nitride barrel and slick-side receiver. Designed specifically for .45 ACP, it includes a dedicated bolt carrier group and charging handle so it can be dropped onto a compatible AR-15 lower for a ready-to-run pistol-caliber build. The upper features a full-length Picatinny rail and a slim free-float M-LOK handguard that keeps the barrel unobstructed while offering ample mounting space for optics and accessories.

This upper is well suited for pistol-caliber carbines, AR pistols, and short-barreled rifle configurations focused on range use, training, and general recreational shooting. The 4" threaded barrel with a 1:16 twist is optimized for standard .45 ACP loads, providing reliable stabilization in a compact package that remains easy to maneuver. TacFire’s attention to detail in machining, materials, and fitment delivers a dependable upper that reflects the brand’s reputation for practical, well-built AR components.

Key Features:

• Manufacturer: TacFire
• Model: BU45ACP4
• Caliber: .45 ACP
• Condition: New
• Action: Semi-Automatic
• Barrel Length: 4"
• Threaded Barrel: Yes (5/8x24)
• What's In The Box: Complete upper with bolt carrier group and charging handle
• Weight: 3.2 lbs