The AR-style rifle designed by Eugene Stoner is the longest running firearm operating system in U.S. Military history, and its semi-automatic version is highly popular on the civilian market.
However, Eugene Stoner designed his AR rifle on the gas-impingement system, which blows powder residue and hot gases into the action. Many people believe this is a major flaw in the gun’s design, which can cause malfunctions, especially in dusty environments.
Frank DeSomma, president of Patriot Ordnance Factory, went to work to fix this problem after taking a hard look at the M16/AR-15 platform while building kit guns with his son.
“I looked at this system from a mechanical perspective, and realized I could improve it,” DeSomma said. “The AR was a great design back in the 50s. What we’ve done is enhance the gun to today.”
What DeSomma came up with is a short-stroke, rotating-bolt, gas-piston system that he calls C.R.O.S. (Corrosion Resistant Operating System). This system eliminates many of the standard parts required on the gas-impingement system such as the gas tube, gas key and gas rings. In addition to the C.R.O.S., DeSomma implemented a two-piece Modular Railed Receiver (M.R.R.) with an oversized heat-sink barrel nut on the P415. These two systems dissipate heat away from the working parts of the gun reducing the bane of ARs—heat.
In fact, DeSomma’s group showed how well his design eliminates heat during a presentation at the NRA’s range by running multiple magazines through the gun in rapid fire before immediately removing the bolt and pressing it against a cheek.
Beyond the obvious improvement to the operating system, the P415 is also designed around an operator’s needs in the field. The M.R.R. is stronger than traditional AR systems to prevent flexing when pulling back on the foregrip under combat stress, and the barrel is free-floated, fluted and chrome-lined for accuracy and durability. The bolt, receiver, extractor, firing pin and gas plug are all coated with NP3 —a mixture of Teflon and electroless nickel—to reduce both friction and needed lubrication in the moving parts. All these features make the P415 a well made, hard-charging modern sporting rifle that won’t fail under fire, and it has some well thought out attributes that can’t go unnoticed.
The ERGO pistol grip is thick, soft and comfortable; the VLTOR Enhanced Carbine Modstock is solid and smooth in its six adjustment positions. The quad-rail fore-end provides ample room for lights, lasers and other accessories, and the monolithic top rail provides a good mounting platform for a variety of optics. It also has an ambidextrous selector switch and bolt release, which really speeds up reloads, and the over-sized trigger guard provides easy access even when wearing thick, cold-weather gloves.
Breakdown is similar to a standard AR with one twist. The upper and lower receivers, as well as the bolt and charging handle, come apart for field stripping like a standard AR. The twist is the gas plug, which can be adjusted for both suppressed and non-suppressed modes, on the front of the rifle above the barrel. After removing the gas plug, which can be released with the bullet of a cartridge if difficult (the only tool needed for basic stripping), the gas piston and op-rod can be removed for cleaning.
While the POF is available in 5.56x45 mm NATO (.223 Rem.), our version came in 6.8 SPC. Testing was conducted for accuracy, reliability and usability since it’s a modern sporting rifle designed for a variety of uses such as self-defense, competition and even hunting.
For accuracy testing, I attached a Nightforce NXS 2.5-10x32 scope and gathered together some Hornady, Remington and Silver State Armory 6.8 SPC ammunition in a variety of bullet weights. For each load, I followed the American Rifleman standard of five groups of five shots at 100 yards, but I also fired a 10-shot group with each load just to see how the rounds would spread as the barrel heated up.
Accuracy was excellent with every load averaging around an inch and a quarter. Overall, the P415 seemed to favor the Silver State ammunition with the 115 grain Sierra OTM loads shooting the best on average; however, the Remington 115-grain Matchking BTHP loads had the best single five-shot group measuring .67 inches.
The 10-shot groups were obviously larger, but were still pretty good, especially since these were conducted toward the end of the day’s session and my energy levels were lower. Once again, SSA had the smallest size group, but this time it was the 85-grain Barnes TSX that led the pack with a 2.1-inch group. Every ammunition brand fired well enough that if the shooter has the skills, he or she should be able to hit whatever target at which the gun is aimed.
Usability and reliability tests were conducted via Diamondhead open sights and a wide variety of ammunition. I started freestanding at 50 yards, and then conducted tactical advance, retreat, double-taps and even triple-taps drills on multiple targets over a period of a few days. While groups couldn’t really be measured, there is no doubt that the P415 would handle any type of tactical use such as three-gun competitions, varmint irradiation and self-defense.
During testing, cleaning was limited to the barrel and an exterior wipe down with no lubrication added at any time. At no point did the P415 fail to load or extract even after hundreds of rounds. The controls were easy to manipulate, and the ambidextrous bolt release definitely made getting back on target faster during. The single-stage trigger was smooth during both accuracy testing and tactical shooting, but it did measure more than the 4.5 pounds listed in the specifications from POF.
DeSomma aspired to build a better AR rifle with user-friendly features, great reliability and really good accuracy. He succeeded. However, at just under $2,000, it’s definitely on the upper end of the price scale, but quality doesn’t come cheap.
“I’m not a big company, so I knew I had to make a quality product,” said DeSomma. “That has been my entire focus.”