• BUILD OF THE MONTH ● JUNE 2026

    AT3 1000 Yard 6 ARC Gas Gun Kit

    This rifle is built for distance, stability, and precision from the AR-15 platform. Every component in this 6 ARC build was selected to support long-range performance, smooth cycling, and confident hits from supported shooting positions.

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  • About the build

    This rifle is built around the 6 ARC cartridge to push the AR-15 platform into longer-range work while keeping the familiar handling of a standard small-frame rifle. We started with an AT3 AT-15 Forged Lower Receiver and paired it with an AT3 Stripped Forged Upper, then added a 20″ 6 ARC target barrel and STNGR VLCN 15.5″ M-LOK handguard for a stable, extended front end.

    For optics, this build uses a Vortex Viper PST Gen II 5-25×50 FFP rifle scope in a 30mm cantilever mount, giving the rifle the magnification range and reticle setup needed for distance shooting. An AT3 ACE red dot on an Arisaka offset mount adds a faster close-range sighting option without disturbing the main optic setup.

    Inside the upper, a Faxon 6.5 Grendel Type 2 bolt carrier group is paired with a rifle-length gas system and Superlative Arms adjustable gas block for proper 6 ARC compatibility and tunable cycling. The Breek Arms Sledgehammer charging handle and Scorch 3-prong flash hider round out the upper with practical upgrades for handling and muzzle control.

    The lower is set up with a Ballistic Engineering GOAT 2-stage flat trigger, Ergo zero-angle grip, ambidextrous safety, extended magazine release, and Phase 5 extended bolt release. For supported shooting, the build includes a Magpul bipod and STNGR ARCA rail adapter, giving the rifle a more stable foundation for prone, bench, or barricade work.
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Upper Receiver Parts

The upper receiver assembly centers around an AT3 Stripped Forged AR-15 Upper Receiver, a STNGR VLCN 15.5-inch M-LOK Free Float Handguard, and a 20-inch 6 ARC target barrel built for long-range performance from the AR-15 platform. Inside, it uses a Faxon 6.5 Grendel Type 2 Bolt Carrier Group for proper 6 ARC bolt compatibility, paired with a Breek Arms Sledgehammer Gas Busting Charging Handle for easier manipulation. The rifle-length gas system, Superlative Arms .750-inch adjustable gas block, and STNGR black nitride rifle gas tube allow the upper to be tuned for smoother cycling, while the Breek Arms Plan B Scorch 3-Prong Flash Hider finishes the muzzle.

Lower Receiver Parts

The lower receiver setup starts with an AT3 Tactical AT-15 Forged Lower Receiver and adds an AT3 Enhanced Trigger Guard, Ergo TDX-0 zero-angle grip, and Ballistic Engineering GOAT 2-stage flat trigger for a more precision-focused control layout. The lower also uses KNS trigger pins, an AT3 ambidextrous safety selector, Battle Arms Development enhanced magazine catch, Odin Works XMR3 extended magazine release, AT3 bolt catch, and Phase 5 extended bolt release for improved handling from supported shooting positions. A UTG Pro mil-spec buffer tube kit, Strike Industries flat wire buffer spring, AT3 castle nut, and Bravo Company QD end plate complete the rear of the lower assembly.

ACCESSORIES

The support gear that helps this 6 ARC build perform from stable shooting positions. A Duramag 26-round 6.5 Grendel/6 ARC magazine handles the cartridge correctly in the AR-15 platform, while the STNGR ARCA adapter, Magpul QR rail grabber, and Magpul bipod give the rifle a stronger setup for prone, bench, and barricade-supported shooting.