FAXON ARAK-21® 12.5" 5.56 BARREL ASSEMBLY UNIT
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FAXON ARAK-21® 12.5" 5.56 BARREL ASSEMBLY UNIT
Faxon ARAK-21® Barrel Assembly Unit — 12.5" 5.56 NATO (1:8 Twist)
Modular, quick-swap barrel assembly for the ARAK-21® system — heavy profile durability in a compact package.
The Faxon ARAK-21® 12.5" 5.56 NATO Barrel Assembly Unit (BAU) is a complete, self-contained module designed for rapid barrel swaps on the ARAK-21® upper receiver. This heavy-profile assembly integrates the barrel, gas block, muzzle brake, gas piston, adjustable gas regulator, and barrel trunnion — delivering reliable long-stroke piston operation in a compact, interchangeable format. Ideal for tactical, defensive, and multi-caliber builds where quick caliber changes and piston-driven reliability matter most.
Key Benefits
- Modular BAU design: Quick-swap barrel assembly for the ARAK-21® — change barrels in seconds with minimal tools.
- Long-stroke gas piston system: Adjustable 4-position gas regulator (3 flow settings + off for single-shot) for tuned reliability and suppressor use.
- Heavy profile barrel: Enhanced durability and heat management in a short 12.5" configuration for compact handling.
- Premium materials: Gun-drilled, reamed, button-rifled from high-quality 4150 CMV steel, fully QPQ black nitride finished for corrosion resistance and longevity.
- Integrated components: Includes gas block with clean-out port, piston, adjustable gas knob, muzzle brake, and trunnion — all pre-assembled.
- Precision manufactured: Made in Cincinnati, OH by Faxon — ensures consistent accuracy and performance in the ARAK-21® platform.
Specifications
Why Choose the ARAK-21® Barrel Assembly Unit
The ARAK-21® BAU enables true modular performance in a piston-driven platform — swap barrels/calibers quickly without tools, enjoy adjustable gas for optimized cycling (including suppressed use), and benefit from the hybrid AR/AK-inspired reliability. The 12.5" heavy profile delivers compact maneuverability with enhanced durability, making it perfect for short-barreled defensive setups or multi-caliber experimentation on your ARAK-21® system.
Installation & Compatibility
- Designed exclusively for the ARAK-21® upper receiver — installs via pivot pin and forearm keys in seconds.
- Integrated long-stroke piston and adjustable gas block — supports suppressed fire and tuned operation.
- Includes pre-installed muzzle brake; compatible with ARAK-21® bolt carrier and recoil system.
- SKU: ARAK21BAUONLY-104S-12 — UPC: 816341029194 — for 5.56 NATO use only.
Frequently Asked Questions
What is included in the BAU?
Is this compatible with standard AR-15 uppers?
Can I use this with a suppressor?
What twist rate and bullet weights are supported?
Overview: ARAK-21® 12.5" 5.56 Barrel Assembly Unit
The Faxon ARAK-21® 12.5" 5.56 NATO Barrel Assembly Unit provides modular versatility and piston-driven reliability in a compact heavy-profile design. Manufactured with precision gun-drilling, button rifling, and QPQ nitride finish, it integrates all key gas system components for quick installation and superior performance.
Every ARAK-21® BAU is built at Faxon Firearms for consistent quality, with an adjustable long-stroke piston system that offers 4 gas settings for optimized cycling across various conditions. Whether upgrading your ARAK-21® setup, adding a short-barreled configuration, or enabling fast caliber swaps, this BAU delivers innovative value from Faxon Firearms.
Warranty Faxon Lifetime Guarantee. Covers manufacturing and material defects to the original purchaser. Excludes damage from misuse, neglect, non-standard ammunition, or modifications. Register your product at faxonfirearms.com/product-registration to expedite service. For purchases through dealers or distributors, warranty repairs are handled directly by Faxon Firearms; refunds must be processed through the selling entity. Full policy: faxonfirearms.com/warranty-privacy-terms/