The heavy-profile barrel is machined from 4150 Mil-B-11595 chrome-moly-vanadium steel alloy, and is full-length fluted to reduce weight, dissipate heat and increase stiffness. An innovative, combination Heat Sink Barrel Nut completely surrounds the chamber end of the barrel, which provides over 65 square inches of heat-dissipating surface area and supports the op rod with almost four inches of bearing surface. The bore is button rifled at 1:10” twist rate, hand lapped and nitride heat treated, making it twice as hard (Rockwell 70C) as hammer-forged barrels and with a bore lining ten times thicker than Mil-Spec chrome lining. The 5-inch long, single-piece gas block/regulator is also nitride heat treated, with a 3-position plug that permits quick selection among normal, suppressor and single-shot modes.
Another POF innovation is their patented E2 Extraction Technology, which features four channels cut into the neck of the chamber. When a round is discharged in a standard chamber, the neck of the case fire-forms to the chamber walls, causing it to stick. E2 Extraction Technology permits small amounts of combustion gas to travel back through the channels along the neck of the case, pushing against the shoulder and breaking it free from the chamber walls. Rather than having to rip the empty case free of the chamber walls, the extractor now simply pulls on a dislodged case. It’s like towing a car in “neutral” compared to trying to tow it in “park.” The result is no more broken extractors, and up to five times longer extractor life.