Proof Research AR-15 Barrel Features The Proof AR-15 Barrel is machined from stainless steel and chambered in .223 Wylde a chamber designed to safely and accurately shoot both .223 Remington and 5.56 NATO ammunition. Its 1:7 twist rate stabilizes a broad range of bullet weights from lighter varmint loads up through heavier match bullets giving shooters flexibility in ammunition choice. Proof s Caliber Matched Gas System or CAMGAS moves the gas port location to match the pressure curve of the cartridge and barrel length rather than relying on a generic AR-15 gas port position. That tuning results in a noticeably softer recoil impulse less fouling inside the receiver and more reliable extraction cycle after cycle. Because the gas system is matched specifically to this barrel s length and chambering it also reduces wear and tear on brass which matters for reloaders and high round count shooters alike. The barrel is threaded 5/8x24 at the muzzle a common AR-15 thread pitch that accepts most aftermarket muzzle devices and suppressors without needing a separate adapter. At 16 inches long it fits within standard rifle length configurations while keeping the rifle maneuverable. For AR-15 owners looking to upgrade to a precision barrel engineered around modern high performance cartridges the Proof AR-15 Barrel is available for sale at GrabAGun. Proof Research AR-15 Barrel Specifications Manufacturer: Proof Research Model: AR-15 Barrel Caliber: .223 Wylde Barrel Length: 16 Barrel Material: Stainless Steel Twist Rate: 1:7 Thread Pitch: 5/8x24 Color: Silver Compatible Hosts: AR-15 Available At: GrabAGun