RADIAN UPPER 18″ 6MM ARC BLACK

Description

Radian’s Model 1 complete upper in 6mm ARC is built for precision rifle work at extended ranges, particularly for shooters who want a platform that balances long-range ballistic performance with the AR-pattern ergonomics they already know. The 6mm ARC cartridge was purpose-designed to extract meaningful long-range efficiency from a standard AR-15 receiver envelope, offering a significantly flatter trajectory and higher retained energy at distance than .223 Remington while still running off the same bolt-face diameter as 6.5 Grendel.

The 18-inch barrel sits in a useful middle ground: long enough to let the 6mm ARC’s case capacity develop velocity close to its ceiling, but short enough to remain manageable in field or positional shooting. A rifle-length gas system spreads the dwell time over a longer travel path, which reduces the sharpness of the recoil impulse and makes the carrier’s rearward motion more gradual — a noticeable difference when running a suppressor or tuning for consistent follow-through. The 1:7 twist rate stabilizes the heavier, high-BC projectiles that make 6mm ARC worth running in the first place; shooters looking to use lighter varmint-weight bullets should confirm stability before committing to a load.

Radian fits the upper with a 17-inch M-LOK handguard, which gives a nearly full-length grip surface and leaves ample real estate for accessories without adding unnecessary bulk. The Raptor-SD charging handle is ambidextrous by design, with a geometry that works equally well suppressed or unsuppressed without requiring the shooter to modify their support-hand grip. The Dead Air KeyMo muzzle brake uses Dead Air’s proprietary mounting interface, allowing direct attachment of compatible Dead Air suppressors without an additional adapter. The barrel carries a Black Nitride finish throughout.