The Proof Research PR15 PXT 6mm ARC barrel (Proof Research part no. 152232) is a 14.5-inch stainless steel barrel for the AR-15 platform that arrives fully chambered and ready for installation. PXT stands for Proof Exponential Twist, a rifling design that eases the bullet into the rifling instead of engaging it abruptly. Proof lists it with an intermediate gas system, a .750 gas journal and a 5/8-24 muzzle thread. At 2 pounds 5 ounces, it suits a compact 6mm ARC upper where you want reach from a short barrel.

Key Specifications

• The chambering is 6mm ARC, and the barrel arrives chambered, so it is not a blank.
• Barrel length is 14.5 inches, a compact length for a handy upper.
• The twist is 1:7.5 PXT, Proof’s exponential twist that starts gently and speeds up through the bore.
• The gas system is intermediate length with a .750 gas journal and a .082 port size.
• The muzzle is threaded 5/8-24, so match a muzzle device to that pitch.
• The material is stainless steel, in a barrel that weighs 2 pounds 5 ounces.

Frequently Asked Questions

Does this barrel come chambered? Yes. Proof states that its PXT AR barrels arrive fully chambered and ready for installation, so this is a finished 6mm ARC barrel and not a blank.

What does PXT mean? PXT is Proof Exponential Twist. Instead of starting at a fixed twist, the rifling begins very slowly and accelerates through the bore, which Proof says reduces engraving force on the bullet and throat wear.

What gas system and muzzle thread does it use? It uses an intermediate-length gas system with a .750 gas journal and a .082 gas port, and the muzzle is threaded 5/8-24.

Buy the Proof Research PR15 PXT 6mm ARC Barrel, 14.5-Inch

If you are building a compact 6mm ARC AR-15 upper, the barrel is where the build is won or lost, and Proof puts its PXT rifling into a finished, chambered stainless barrel here. Order it from our Lubbock, Texas shop for fast direct shipping, and see more AR-15 barrels while you are here.