Faxon Firearms Match Series 338 ARC Gunner Complete Upper - 12.5"

Everything above the lower, assembled and ready to run — the Faxon Match Series 338 ARC Gunner Complete Upper delivers 338 ARC-specific feed ramps, a patented adjustable gas block, and Plan B-compatible suppressor mounting in a 12.5" package built for suppressed pistol and SBR builds.

The Faxon Match Series 12.5" 338 ARC Gunner Complete Upper is a fully assembled drop-in complete upper receiver group featuring a purpose-modified 338 ARC upper receiver with caliber-specific feed ramps, patented adjustable gas block, MuzzLok Plan B flash hider, and Type 2 ARC BCG with gas-blocking charging handle installed.

338 ARC demands a feed path engineered for its case geometry — standard AR-15 uppers with 5.56 feed ramps are not designed for 338 ARC and will not reliably cycle this cartridge. This upper's purpose-modified feed ramps are the most commonly overlooked component in 338 ARC builds. The Faxon patented adjustable gas block lets you tune dwell time for suppressed versus unsuppressed use and across subsonic and supersonic loads — critical for consistent cycling across 338 ARC's full ammunition range. The MuzzLok Plan B flash hider (5/8x24, .375" bore) provides direct suppressor compatibility without additional adapters.

• Caliber: 338 ARC
• Barrel Length: 12.5"
• Barrel Profile: Gunner (Match Series)
• Twist Rate: 1:8
• Rifling: 5R
• Gas System: Pistol-Length
• Upper Receiver: 338 ARC Enhanced Forged (338 ARC-specific feed ramps)
• Gas Block: Faxon Patented Adjustable .750" Low Profile
• Gas Tube: Pistol-Length Stainless
• Handguard: Faxon Streamline 10.75" M-LOK
• Muzzle Device: MuzzLok Plan B Flash Hider, 5/8x24, .375" bore
• BCG: Faxon SuperFinished Type 2 ARC Nitride (included)
• Charging Handle: Faxon Edition Breek Sledgehammer gas-blocking (included)
• Product Type: Complete Upper Assembly

Compatibility Note: This upper features 338 ARC-specific feed ramps engineered for 338 ARC case geometry. Standard AR-15 uppers with 5.56 feed ramps are not compatible with 338 ARC. Compatible with mil-spec AR-15 lowers. The Type 2 BCG has the correct bolt face for 338 ARC. Plan B-compatible suppressors mount directly to the 5/8x24 MuzzLok Plan B flash hider with no additional adapter. The Breek Sledgehammer gas-blocking charging handle manages suppressor blowback during suppressed use. Lower receiver, brace/stock, and magazines sold separately.

Match Series Gunner profile barrel with 5R rifling and 1:8 twist is built for the full range of 338 ARC projectiles from 175gr subsonic to 270gr+ supersonic loads in a compact pistol-length package.

Best for suppressed SBR and pistol builds in 338 ARC, builders who need correct 338 ARC feed geometry from the start, and those who want a complete upper with BCG and charging handle ready to drop on a lower.

Faxon Firearms builds every Match Series barrel in-house at their Cincinnati, Ohio facility, with in-house MPI inspection and quality control across the full upper assembly.