Looking for a tougher, more reliable AR-15 upper that drops onto your existing lower with zero modifications? The ARAK-21 from Faxon Firearms is the game-changing complete upper receiver assembly you’ve been waiting for.
Why the ARAK-21 Stands Out
- 100% Gas Piston Operated – Cleaner, cooler, and more reliable than direct impingement, especially with suppressors or short barrels.
- Seamless AR-15 Compatibility – Installs in under 1 minute using only your standard takedown and pivot pins. No gunsmithing, no new lower, no tools required.
- Barrel Assembly Unit (BAU) – Includes barrel, gas block, muzzle brake, gas piston, adjustable gas regulator, and trunnion. The only user-removable part is the 4-position gas adjuster knob:
- Normal (unsuppressed)
- Adverse/suppressed
- Heavy use
- Off (single-shot mode)
Premium Features Included
- Full-length aluminum Picatinny rails on top and both sides
- Heat-resistant insulating shims
- Ambidextrous charging handle block
- Heavy-duty bolt carrier with dual recoil spring system for reduced felt recoil
- Quick-change barrel capability (swap calibers or lengths in minutes)
Minimal AR-15 Parts Interchangeability
Only the firing pin, extractor spring, and ejector spring are standard AR-15 parts – everything else is purpose-built for maximum durability and performance.
Perfect For
- Suppressor users
- Hard-use rifles
- 300 Blackout or 5.56 builds
- Anyone wanting a piston AR without buying a whole new rifle
Upgrade your AR-15 to piston-driven perfection in seconds. The ARAK-21 delivers legendary AK-style reliability with AR-15 modularity.
Ready to go piston? Grab your ARAK-21 upper at Krinkov.com today.
(Compatible with mil-spec AR-15 lowers – no modifications needed.)