POF P-415 Gas Piston/Op-Rod-Driven Tactical AR Carbine: Real Low Maintenance

Print Friendly, PDF & Email

By Charlie Cutshaw

Revolutionary is a word that is occasionally inappropriate, but sometimes it is about the only word that fits. Suppose we told you that we had fired a new AR based rifle that didn’t need lubrication? And suppose we told you that it really didn’t need regular cleaning, either? Finally, suppose we told you that this new AR would run over 20,000 rounds without a failure? You’d probably think that Cutshaw needed to turn himself in for a drug test, a reasonable but erroneous conclusion. Such an AR upgrade does exist and it has been used extensively by Don Alexander, Co-Director of Training at SHD Consulting. The figures that follow are his, not mine. Alexander set out to shoot the P-415 upper receivers he got from Patriot Ordnance Factory (POF USA) without cleaning or lubing them until they started to malfunction. He never made it.

Alexander’s rifle was cleaned for the first time at the 16,000 round mark, not because the P415 needed it, but because he was teaching a course for the State Department that mandated a class on cleaning and maintenance. Since then Alexander has put more than 3,000 rounds through his P415 upper without cleaning or lubrication. In a memo to Frank Desomma, President of POF-USA, Alexander stated that…

he had yet to experience a single malfunction except one that was attributable to a faulty magazine very early in his use of the P-415 upper. Alexander, a retired US Army Special Forces Chief Warrant Officer with 26 years’ experience, is not one to make statements such as these lightly or in jest. Like Alexander, the P415 is the “real deal.”

POF has entered the market with an AR-type rifle that is unlike any other. Externally, the most obvious difference between the P415 and others is the patented Predator upper receiver that not only features an uninterrupted full length MIL-STD-1913 top rail and rails at the handguard sides and bottom, but also free floats the barrel, enabling mounting accessories without affecting the rifle’s zero. Our P415 came with a 16 inch barrel, but is also available as a rifle with a 20 inch barrel. The select fire version is designated P416 (a.k.a. P-416). The P415 barrel is fluted along its entire length for rigidity and heat dissipation. The flutes offer a greater surface area, so heat is more rapidly dispersed that with standard heavy barrels. Flutes also stiffen the barrel and improve accuracy by reducing barrel vibration as the rifle is fired. Our test rifle also came equipped with a Vortex flash suppressor, one of the most effective such devices available. Our P415 was equipped with a finned heat dissipater near the breech end of the barrel. When used heavily in full auto, heat buildup at the breech area of the barrel and forward area of the upper receiver is a problem. While the P415’s gas system minimizes heat transfer by not injecting hot gases into the receiver, for full military or law enforcement SWAT use the cooling fins are added insurance against unwanted heat transfer. Fit and finish of the P-415 are excellent. We were particularly impressed with the mating of upper and lower receivers with absolutely no “play” whatsoever. POF’s P415 is one of the best assembled AR-type rifles we have ever seen.

One of the major differences between the P415 and any other is the patented gas system that eliminates the inherent problems associated with Stoner’s original design. The original AR direct impingement gas system not only blows large amounts of fouling and particulate matter back into the receiver, but also causes excessive heat to be transferred to the receiver area in rapid semiautomatic or full automatic fire. There have been attempts to solve the AR’s gas system problems in the past, but POF is one of the most innovative. The P415 gas system consists of a FAL-type gas cylinder plug, a six-inch chrome lined gas cylinder with a chrome plated stainless steel piston and operating rod that impinges against a reinforced bolt carrier key. Unlike some other “op rod” systems, there are no springs on the Predator rod. Heat from sustained firing may damage springs that surround op rods that are in close proximity to the barrel. This is especially true in select fire rifles. The P415 gas system is self-regulating. The P415 system can be easily and quickly disassembled by simply pressing in on the gas cylinder plug button while rotating the plug clockwise. Once the plug is removed, the piston and operating rod fall out when the muzzle is pointed down. Reassembly is accomplished simply by dropping the rod back into the gas cylinder with the muzzle pointed up. If it doesn’t fall into place, all that is necessary is to shake the upper receiver – the rod will fall. The piston is replaced with the gas rings forward. The plug fits only one way and cannot be incorrectly reassembled. All that is necessary is to push the plug into place, press the locking button and rotate the plug counterclockwise.

When the P415 shooter decides that his or her carbine should be cleaned, after exposure to the AR’s direct gas impingement system, P415 maintenance is a true revelation. While conventional AR receivers fill with fouling and particulate matter after a few rounds, the POF P-415 remains clean even after extensive firing. There is no carbon fouling or caked carbon to be found on the bolt or in the bolt carrier recesses. In short, the P415 is much easier and simpler to maintain than any AR-type rifle with the usual direct impingement system. The P415 gas system is a really significant step forward in AR design. While Don Alexander has shot thousands of rounds through his P415 without cleaning, prudence dictates that any rifle should get a periodic scrub. In the case of the P415, all that is necessary is to wipe the receiver’s interior, bolt carrier and bolt with a dry shop towel to remove any fouling. Also, the gas system should be disassembled and cleaned, since it takes the brunt of hot gases from the barrel. Any carbon buildup in the gas system can be removed with a Scotch Brite pad.

But the improved gas system isn’t the end of the story with the P415. The changes that allow the P-415 to run without lubrication are a chrome plated bolt carrier and bolt coupled with silicon nickel plating on the receiver’s interior and on the charging handle. Nothing sticks to either surface and they are self lubricating. The bolt carrier has been modified for increased reliability and accuracy. The bolt carrier surfaces that ride on the upper receiver are somewhat larger than conventional ones, while maintaining recesses to accommodate any fouling that might accumulate. The chamber, barrel locking lugs and interior are also chrome plated, which enhances reliability. As a top-end AR-type rifle, the P415 has virtually all the options to make the rifle as close to perfection as possible. Our test rifle had a single stage Accuracy Speaks match trigger that broke like a glass rod at precisely 3.5 pounds with zero creep or backlash.

While the POF USA P-415 is excellent in its own right, some recently developed accessories transform any AR-type rifle. One is Vltor’s Modstock. The Modstock is available in several colors and configurations, including black, coyote tan and OD green. There are two collapsible Modstocksstandard and “clubfoot.” The clubfoot facilitates using the off hand to pull the stock into the shoulder for greater stability. Unlike most others, Vltor’s waterproof compartments can be accessed with the stock on the carbine. The compartment adapters provide a flat surface for an excellent cheek weld. The Vltor Modstock is extremely comfortable and thus enhances accuracy. It also raises one’s line of sight to an ideal level for either open sights or optics. The improvements don’t end with comfort and utility, though. Vltor also redesigned the latch on both standard and clubfoot configured stocks. The Modstock also offers several different sling options. The standard M4 sling can be used, but the Modstock has a provision for Uncle Mike’s quick detachable sling swivels, one of which is provided in the Modstock modification kit. The Uncle Mike’s sling swivel can be fitted to either side of the stock. We should note that there are two outside diameter (OD) sizes of carbine drive spring tubes. Military standard OD carbine tube diameter is approximately 1.150 inch, while most commercial drive spring tubes have an OD of about 1.170 inch. Threads for screwing the tube into the lower receiver are the same on both. Our P415 had the commercial tube, so we had to install Vltor’s complete stock kit, consisting of Modstock, drive spring tube, drive spring and buffer. While the drive spring tube was removed, we added a Buttonsling back plate that adapts the carbine to a single point Buttonsling. The Buttonsling takes its name from the “button” on the back plate that allows the sling to be removed and replaced. Like most single point slings, the Buttonsling positions the carbine straight down and in the center of the shooter’s body, allowing a quick transition to the pistol. If it is necessary to remove and install the drive spring tube, a special wrench is needed and there are small parts and springs in the lower receiver that can become lost or damaged when removing and replacing the tube and back plate.

Since most military and law enforcement carbines today are equipped with optical sights, we added an Aimpoint CompM3 with optional 3x magnifier, the company’s latest military/LE red dot sight that is available with either a 2 or 4 minute of angle (MOA) red dot. Our test unit came with the smaller 2 MOA dot, which we prefer. Red dot sights are much faster on target than open sights because the shooter aims with both eyes open and as he shoulders his rifle, he instinctively places the dot on target without having to concern himself with sight alignment, the major cause of inaccuracy with open sights. The Aimpoint Comp M3 is waterproof to 135 feet (45 meters), operates within a temperature range of -50 to 160 degrees, Fahrenheit and has a battery life of approximately 50,000 hours, based on setting the red dot at higher levels of intensity. The CompM3 is protected by a rubber cover that is available in either black or dark earth. The Comp M3 has the features that made earlier versions favorites of military and law enforcement agencies worldwide – zero parallax, unlimited field of view and rock solid reliability.

The Aimpoint 3XMag adds to the Comp M3’s versatility by turning the carbine on which it is mounted into what Aimpoint calls a “semi-sniping” rifle that can be returned to a CQB weapon in an instant. The 3X Mag attaches and detaches in a split second on Aimpoint’s “Twistmount” by simply pressing a button and giving it a 90 degree turn. The Aimpoint 3X Mag can also be used as a handheld monocular if necessary. There is no affect on point of aim or impact. Like the Comp M3, the 3X Mag is extremely rugged, light weight and functions in temperatures ranging from -50 to 160 degrees, Fahrenheit.

Shooting the P415 was a revealing experience – one that showed just how different this new carbine is from conventional AR-type rifles. Not only was the carbine notably accurate using the “red dot” Aimpoint that basically covered the bullseye at our 100 yard test distance. As such, the carbine easily can achieve “head shots” at 100 yards using the Aimpoint and 3x magnifier. Since red dot sights are less precise than optics with true reticles, we informally tested the P415 with a 1-4x Horus Vision Talon CQB – mid range scope and a US Optics 3.2 –17x with Horus Vision H25 precision tactical reticle. Shot groups with the Talon using Black Hills 77 gr match ammo, identical to the military Mk262, Mod 0 (or Black Hills MK262 Mod 1), averaged an inch. The US Optics precision tactical scope reduced group size to almost exactly 0.75 inch, excellent for a 16 inch carbine. Functioning was flawless. The single stage match trigger broke like snapping a glass rod at exactly 3.5 pounds. This carbine’s operation was also much smoother than we usually expect from AR-type rifles, attributable to the gas trap operating system. Felt recoil was also minimized, along with muzzle rise, enabling quick recovery and follow-up between shots.

POF’s P415 breaks new ground in the world of AR-type rifles that are otherwise so similar that even experts cannot tell the difference between one and another without close inspection. Its innovative “gas piston/op rod” significantly advances the “state of the art” in AR-type firearms and not only adds flexibility to the overall system, but improves both reliability and maintainability over any of its conventional competitors. No gas operated rifle is totally maintenance free, but the POF P415 is about as close as it comes. The P415’s innovations are among the most significant developments in AR type rifles since they were originally designed over 40 years ago.

Shooting Results: POF P415 Carbine







Group Size

Hills 77gr HPBT















62 gr FMJ






3 in

Testing conducted at Sheffield, AL Police Department Range, temp 87 deg, F. 100 yards distance. Velocity data recorded using Oehler 35 Chronograph. Accuracy average of two five shot groups. *Excludes called flyer.

POF P415 Specifications:

Caliber: 5.56x45mm (.223 Remington)
Operation: Gas, semiautomatic, piston & operating rod
Overall length: 35.75 inches*
Barrel Length: 20 or 16* inches
Length of pull: 13.5 inches
Empty weight: 9.5 lbs**
* As tested
**As tested weight includes Laser Devices MOLAD laser/white light illuminator, Tango Down vertical foregrip and Aimpoint sight.

Company Contact Info:

Patriot Ordnance Factory, Inc. (POF USA, Inc.)
23623 N 67th Avenue
Glendale, AZ 85310
Tel: 623-561-9572

Aimpoint, Inc.
7702 Leesburg Pike
Falls Church, VA 22043
Tel: 703-749-2320

Vltor Weapon Systems
3735 N Romero Road
Tucson, AZ 85705

SHD Consulting:

Harry Fleming

Don Alexander

Dianne Fleming


The above article originally appeared in the April 2007 Issue of Guns & Weapons for Law Enforcement (GWLE).

Related Articles:

KAC 6x35mm PDW (Personal Defense Weapon) Gets Test-Fired at the Range

FERFRANS Combat Rifles and GRSC Combat Rifle Scope (CRS) at the Range

LWRC M6A2 Gas Piston Weapons at NDIA Small Arms Symposium 2007

DefRev Exclusive! MagPul PDR (Personal Defense Rifle) 5.56 PDW (Photos!)

MagPul Masada Adaptive Combat Weapon System (ACWS) Makes Its Debut

DefRev Quick Hits 2: More ‘Latest and Greatest’ Tactical Tech from the Show

HK416 Piston-Driven 5.56 Carbine and High-Reliability 30-Round Steel Mag

DSA Z4-GTC (Gas Trap Carbine) vs. Arms Tech Compak-16 vs. HK416?

DSA Z4-GTC (Gas Trap Carbine) at SHOT Show 2005

POF P-415 Gas Piston/Op-Rod-Driven Tactical AR Carbine: Real Low Maintenance by

About David Crane

David Crane started publishing online in 2001. Since that time, governments, military organizations, Special Operators (i.e. professional trigger pullers), agencies, and civilian tactical shooters the world over have come to depend on Defense Review as the authoritative source of news and information on "the latest and greatest" in the field of military defense and tactical technology and hardware, including tactical firearms, ammunition, equipment, gear, and training.

Check Also

New KAC KS-1 Tactical AR-15 Carbine/SBR with New Reduced-Back-Pressure Suppressor! (Video!)

By David Crane david (at) defensereview (dot) com February 20, 2024 O.k., we’re back. Sorry …