AR 15 Rifle Build Kit with 20" Barrel

AR 15 Rifle Build Kit with 20" Barrel

Everything you need to complete a full-length AR build—precision, power, and heritage.

The AR 15 Rifle Build Kit with 20" Barrel combines classic M16A2-style aesthetics with modern enhancements for a dependable, accurate rifle build. At its core is the Dirty Bird 20" M16A2 Enhanced 5.56 Upper Assembly, featuring a lightweight 1:9 twist barrel, rifle-length gas system, and A2 furniture. It’s paired with a complete mil-spec lower parts kit, A2 buttstock kit, black nitride .223/5.56 BCG, and an enhanced 7075-T6 charging handle—all carefully selected for compatibility, durability, and ease of assembly.

This kit includes everything you need to complete your stripped lower receiver and achieve a functional rifle-length build with upgraded internals and clean, retro styling.

Included Components

• Upper Assembly
  • 20" 5.56 Lightweight Contour Barrel (1:9 Twist, Rifle-Length Gas)
  • M16A2 Forged Upper Receiver w/ A2 Front & Rear Sights
  • A2 Handguards & A2 Flash Hider
• Lower Parts Kit
  • Full mil-spec components with A2 pistol grip and standard FCG
  • Includes all pins, springs, selector, and trigger group
• A2 Stock Kit
  • Fixed A2 buttstock with storage compartment
  • Rifle-length buffer tube, spring, spacer, and buffer
• Bolt Carrier Group
  • .223/5.56 Black Nitride BCG
  • 9310 steel bolt, MPI inspected, D2 extractor, and chrome firing pin
• Charging Handle
  • Mil-spec style, 7075-T6 aluminum
  • Enhanced grip surface with hardcoat anodized finish

Specifications

• Caliber: 5.56 NATO
• Barrel Length: 20"
• Gas System: Rifle Length
• Twist Rate: 1:9
• Platform: AR-15
• Upper Receiver: M16A2 Forged, Anodized
• Stock: A2 Fixed
• BCG: Black Nitride, 9310 Steel Bolt
• Charging Handle: 7075-T6 Enhanced Mil-Spec
• Compatibility: Works with any mil-spec AR-15 lower

Note: This kit includes everything except the stripped lower receiver.