The complete upper (this product, FX-URG-M33A125GA1075-C-SR) ships with the Faxon SuperFinished Type 2 ARC Nitride BCG and the Faxon Edition Breek® Sledgehammer gas-blocking charging handle already installed inside the upper. The barreled upper (FX-URG-M33A125GA1075-BU-SR, $660) ships without a BCG or charging handle — better for builders who already have preferred components. Both use the same 338 ARC enhanced upper receiver with modified feed ramps, same barrel, same gas system, same handguard, and same muzzle device.

338 ARC uses a larger-diameter .338-caliber projectile seated in a case designed around the 6.5 Grendel/ARC bolt head. The case geometry — specifically the shoulder and neck dimensions — is meaningfully different from 5.56 NATO. Standard M4/M16 feed ramps in a conventional AR-15 upper receiver are cut for the 5.56/.223 case family and can cause feeding issues, particularly with heavier subsonic projectiles, when used with 338 ARC. The Faxon 338 ARC Enhanced Forged Upper Receiver features modified feed ramps cut specifically for the 338 ARC case profile, optimizing reliable feeding across the full range of supersonic and subsonic loads.

Yes. The upper ships with the Faxon MuzzLok Plan B compatible flash hider (5/8×24, .375" bore), which accepts Plan B compatible suppressors via direct mount — no additional adapter or mount required. The Faxon patented adjustable gas block allows you to tune dwell time for your specific suppressor, host, and ammunition combination. The Breek Sledgehammer charging handle is also included to manage suppressor gas at the shooter's face. You still need to purchase the suppressor separately and complete any required NFA paperwork.

338 ARC uses the same magazine body as 6.5 Grendel and standard AR-15 — it requires a Type 2 follower designed for the larger-diameter 338 ARC cartridge. Standard 5.56/.223 followers will not properly feed 338 ARC rounds and are not recommended. Dedicated 338 ARC magazines from compatible manufacturers are the correct choice. The magazine is not included with this upper.

This upper is compatible with any standard mil-spec AR-15 lower receiver. No special lower is required for 338 ARC — the cartridge change is entirely in the upper (barrel, upper receiver, BCG bolt face). The Faxon Forged AR15 Lower Receiver is a good match for a complete Faxon build. You will need a lower parts kit, trigger group, and stock or brace separately.

No. This is a complete upper receiver assembly — it is a firearm component, not a regulated firearm under federal law. Upper receivers do not have a serial number and do not require an FFL transfer in most jurisdictions. However, if you intend to build a short-barreled rifle (SBR) using this upper with a lower receiver and a stock, the resulting firearm is an NFA-regulated SBR requiring ATF Form 1 or Form 4 approval and applicable tax stamp. Verify your local and state regulations before purchasing. Faxon recommends consulting with a licensed FFL/SOT dealer for guidance on SBR builds.

The Faxon Match Series 338 ARC Complete Upper is designed, machined, and assembled by Faxon Firearms in Greater Cincinnati, Ohio. Faxon has operated as a precision machining company since 1978.