Proof Research PR15 PXT AR Barrels Features The Proof Research PR15 PXT AR Barrels is built around PXT PROOF s Exponential Twist rifling technology a rethinking of conventional twist progression engineered to smooth projectile engagement into the bore. This reduces engraving force and throat erosion as a round transitions into the rifling which in testing has shown meaningful increases in barrel life while holding to PROOF s accuracy standards. The reduced rifling lead angle also lowers felt torque during firing helping the rifle track straighter under recoil and stay on target through faster strings of fire. Chambered for 6mm ARC with a 1:7.5 twist this 18 barrel is matched to the cartridge s heavier-for-caliber bullets for extended-range performance. Wrapped in PROOF s carbon fiber barrel technology this barrel sheds considerable weight compared to a steel equivalent without sacrificing the stiffness needed for consistent harmonics shot to shot. It ships fully chambered with a .750 gas journal a .096 port and a 5/8x24 threaded muzzle ready to accept a comp or suppressor so it drops into a compatible AR upper as a straightforward upgrade. The rifle-length plus one gas system is tuned for reliable cycling in a mid-to-long gas gun configuration. For builders refining an existing AR or assembling a new 6mm ARC upper from the ground up this barrel delivers PROOF s next-generation barrel technology in a lightweight precision-focused package. Proof Research PR15 PXT AR Barrels Specifications Manufacturer: Proof Research Model: PR15 PXT AR Barrels Caliber: 6mm ARC Gun Platform: AR-15 Barrel Material: Carbon Fiber Barrel Length: 18 Twist Rate: 1:7.5 Gas System: Rifle +1 Length Gas Journal: .750 Port Size: .096 Thread Pattern: 5/8x24 Grooves: 5 Weight: 1 lb 14 oz Available At: GrabAGun