ABOVE: The original POF rifle in its Gen 1 configuration. The first rifles were chambered in 5.56mm. The upper receiver is a standard forged upper with a standard M4-type handguard. Notice the gas block is drilled and pinned in place. This rifle is basically the M4 configuration with DeSomma’s new gas system.

The short stroke/long stroke piston operated AR-type rifles are fairly mainstream now. Many manufacturers build dedicated rifles as well as drop-in conversion kits. In the late 1990s and early 2000s though, it was a very new concept. Although short stroke pistons systems go back to 1968 with the Winchester conversion and the long stroke piston approximately the same time with the Colt model 703, the system just never got any forward movement. After the initial issues were corrected, the M16A1 went on to become one of the most reliable rifles in history. In the late 1980s, it came around again with the Rhino System designed by Walter Langendorfer. He had military potential but was shut down by Army bureaucracy.

In the early 2000s, the industry was taking a real hard look at the benefits of an external piston operated rifle. The actual dates are not necessarily for sure as the companies showed prototype rifles prior to the beginning of production. Based on the years of production there were three main companies that drove the external piston into market as well as into the hands of soldiers, law enforcement and the commercial market. In 2004, the Patriot Ordnance P416 first began shipping. In 2005, Heckler & Koch released their HKM4 Enhanced/HK416 and in 2006 LWRC introduced their M6.

The Gen 2 rifle showed several changes. First being the lower receiver where the trigger guard is now integral to the receiver. POF also introduced their high free floating handguard. This Gen also marks the introduction of the POF manufactured trigger as well.

In 2002, Patriot Ordnance Factory was incorporated by the owner, Frank DeSomma. This Brooklyn, New York native never even thought about guns in his early years. New York City is less than a gun friendly environment. His family uprooted to Arizona where all that was about to change. Frank started off as a kid with his friends building trucks and Jeeps fabricating custom vehicles. After that Frank spent 28 years in the Aerospace industry as a manufacturing process engineer. He had friends who were involved in hunting – mostly dove and deer – and Frank got introduced to standard hunting firearms. Franks best friend introduced him to the AR-15. Frank was enamored by the rifle and the design genius of Gene Stoner. He decided he wanted to get into the AR business. He knew he could not compete with companies like Colt, DPMS, Bushmaster and so on. He knew if he was to succeed he had to offer the customers something different. He began his company selling parts and accessories and then went on to develop his own rifle. Frank stated that the freedom of this country offered him the opportunity to go into the gun business.

Frank recognized the excellent attributes of the AR-15 but decided to change the operating system to eliminate heat and fouling in the action. He also decided to increase reliability in the system by using an external piston operating system. According to Frank, his design approach was to start backwards from the gas block on the barrel and ending at the chamber. First he moved the gas cylinder to the gas block instead of inside the bolt carrier; then a valve to select suppressed and un-suppressed positions. This valve is critical in extending the service life of the firearm when using a sound suppressor. Without the valve, the sound suppressor increases internal pressures driving the cyclic rate up, which opens the bolt sooner and causes more wear on the internal components. Failures to extract are one of the first casualties of suppressed weapons. He designed this system to work with both semi as well as fully automatic firearms. The 5.56mm rifles maintain a cycle rate of 750 to 850 rounds per minute and the 7.62x51mm rifles maintain a cyclic rate of 650 to 750 rounds per minute. Then he designed the operating rod and bolt carrier for his system.

The Gen 3 rifles introduced the ambidextrous magazine and bolt catch as well as the POF designed muzzle brake.

In 2004, the first rifles left the Patriot Ordnance Factory; this was the Flagship Model P416. This is the early rifle with the high rails not to be confused with the later generations with plastic handguards or added rail. The first generation utilized a standard mil-spec lower from a forging. The 2-piece rail was designed and manufactured by POF. The barrel is free-floated.

The Gen 2 rifle had one major change. POF made lowers from a billet and the trigger guard is integral with the receiver. The heat sink barrel nut was introduced on this model, which helped radiate heat away with 53 inches of surface area made of aircraft grade aluminum. This long barrel nut also helped a support 4 inches of the op rod.

The Gen 3 was introduced with the new upper and lower receivers manufactured from billet 7075 T6 aluminum. Also the ambidextrous bolt release was added. This was one of the first integral ambidextrous bolt releases in the industry. Also introduced in this generation is the enhanced roller cam pin. The cam pin has a roller on the top of it that reduces friction and drag of the action while cycling. The head of the cam pin rolls when it engages the receiver wall and eliminates the worn groove and wear on the receiver. The roller cam pin is available for both 5.56mm and 7.62mm rifles. It may be purchased as an accessory as well. The 7.62mm bolt carriers require no modifications. However the standard 5.56mm direct gas impingement carriers require a special carrier key with a cut out to allow for the clearance of the roller cam pin.

The current Gen 4 has the newly crafted lower receiver, which has many improvements to the ergonomics of the lower receiver. It makes the rifle easier to handle and manipulate. Notice the groove machined into the lower in front of the trigger housing for the trigger finger so there is a place to rest your trigger finger off of the trigger.

The current model is the Gen 4. Many changes have been added to the ergonomics of the receivers that included an ambidextrous magazine release. Also, a bolt hold open lever was added in front of the trigger inside the trigger guard that by pushing upward on the lever and pulling the bolt to the rear would lock the bolt open. The trigger guard is elongated to allow the use of heavy gloves and there is a trigger finger rest divot machined into both sides of the receiver. Also introduced in this generation is a tension screw to adjust the tension between the upper and lower receiver.

POF serializes all barrels to gas blocks when they machine the gas block to the barrel. They separate the barrel from the gas block and have the barrel and gas block heat treated. The barrel and gas block will not rust or corrode because POF processes them separately. All barrels, gas blocks, upper, lowers, regulated gas plugs, drop in triggers, bolt carriers, receiver extensions, free float rail and .308 extractors
are date coded.

Perhaps one of the greatest design enhancements of the Patriot Ordinance Factory is the Push/Pull E Squared Extraction Technology. With shorter barrels (less than 20 inches), the cartridge case is still slightly obturated at the moment of extraction. This causes the extractor spring as well as the actual extractor be a little more overworked than in the standard full size rifle. With the direct gas impingement rifles, as the rifle wears, the gas port inside the barrel will erode allowing more gas to enter the system making the cyclic rate increase even more from when the rifle was new. This causes even more strain on the extractor and extractor spring. This technology features a four channel cut in the neck to help break the seal of the neck from the chamber walls during the delay from when the cartridge is fired to the gasses pushing the bullet down the barrel. The hardest the extractor works now is to exercise over the rim of the case every time the cartridge is chambered.

Perhaps one of the biggest breakthroughs in POF development is their E Squared extraction enhancement system. Note the four cuts in the neck part of the chamber.

There are commercial as well as law enforcement and military versions of the rifle. The military and law enforcement versions are offered in selective fire models. POF offers rifles in black anodized, NPS, Cerakote Tungsten, olive drab or burnt bronze colors. All bolt and barrels are magnetic particle inspected to ensure against stress cracks and are tested with proof cartridges when it is requested.

There were two rifles sent to SADJ for test and evaluation: the P-308 7.62x51mm rifle and the newly released Puritan 5.56x45mm rifle. The P-308 is a Gen 4 rifle with all of the most up-to-date enhancements offered by Patriot Ordnance Factory. The Puritan is a new product that was introduced as an entry level rifle, which is more cost effective. The rifle goes back to the Gen 1 in that it uses standard forged receivers rather than the billet receivers.

The Puritan is one of the finest built piston rifles on the market today. The fit and finish is second to none. Although designed as an entry level rifle, it has all the mechanical features of its counterpart the P415. Though primarily chambered in 5.56x45mm, the rifle can also be chambered in 6.8mm SPC.

With the cartridge in the chamber and it being fired, note how the hot high pressure gasses leak back through the notches in the chamber and how they impart right on the shoulder of the fired cartridge case. This starts the extraction process prior to the extractor engaging and in turn decreases the wear on the extractor severely. This would be a major improvement on any 5.56mm or 7.62mm auto loading rifle.

Beginning at the rear of the rifle, the 7 position mil-spec receiver extension is manufactured from 7075 T6 impact extrusion by POF. The receiver extension is designed as an anti-carrier tilt mechanism. There is a ramp on the end to properly align the bolt carrier when it enters the receiver extension, which eliminates the issues caused by carrier tilt found in external piston operated AR-type rifles and the bolt carrier is sitting in the receiver extension when the receivers are closed. The buffer used is a standard carbine buffer with three steel weights. Due to the design of the operating mechanism, it is not over gassed that would cause bolt carrier bounce issues. The rifle is equipped with a Magpul CTR stock.

The lower receiver has an ambidextrous safety manufactured by POF. The trigger used in the rifle is POF designed and manufactured. This single-stage, non-adjustable, drop-in trigger boasts a solid 4.5-pound pull weight and is pre-assembled in Hardcoat Anodized aluminum housing (complete with rubber urethane feet) for immediate competition, hunting, and tactical applications right out of the box. POF also offers this same trigger in 4 pounds. Carved from American A2 steel, the trigger, disconnect, and hammer are all Nitride heat-treated to 70 Rockwell case hardness for ultimate strength and corrosion resistance. The trigger pull on the T&E rifle broke at 4 and 1/2 pounds. It should be noted POF helped to develop the Timney Trigger. It includes custom-fit stainless steel KNS Precision Anti-walk Pins for both standard AR and POF-USA ambidextrous lower receivers. The trigger is easily installed.

On the top of the lower receiver, just in front of the rear takedown pin are two polymer hex screws that are adjustable to control the play in the upper and lower receivers. On most rifles, you have to remove the pistol grip to adjust the tension between the receivers but POF makes it so you will not have to remove the grip as the tension screws are right out in the open and convenient to get to. The bolt catch has been redesigned so there is a larger “paddle” located at the bottom of the bolt catch making for easier operation. The T&E rifle is also equipped with a Magpul MOE pistol grip and Magpul enhanced trigger guard.

The POF P-308 Gen 4 rifle being put through its paces. Note the fired cartridge case.

The charging handle is also of POF design. There are knurled edges on the front and rear permitting easier and more positive grip whether you are right
or left handed.

The bolt carrier is nickel plated and is a one-piece design with the tombstone/operating rod impact area being behind the cam track. The carrier is the full auto configuration. The bolt is chrome plated and is a standard mil-spec bolt. This bolt was just missing the unneeded gas rings. The extractor has a rubber “O” ring around the extractor spring, which increases the extraction force by a factor of 4. This is “insurance” that really expands the life of the extractor spring. In fact, with this alone, the extractor spring is really not even needed. The carrier uses the roller cam pin which is NP3 coated. The firing pin is the standard mil-spec chrome plated firing pin with a standard firing pin retainer pin.

The upper receiver is a standard mil-spec upper with a mil-std 1913 rail, forward assist and fired cartridge case deflector. The ejection port cover has laser engraved an American Flag and written “God Bless America.” On this rifle, the upper and lower receivers are a perfect match of jet black color. There is a standard barrel nut, Delta ring, spring weld and snap ring.

The gas system of the POF puritan removed showing the operating rod, piston and gas plug. The operating rod is held in-line by the long sleeve at the rear of the gas block.

The 16.5 inch barrel is manufactured from 4150 chrome vanadium Mil-V-11595 steel and is Nitride heat treated. The rifling has 5 lands and grooves and is 1 turn in 8 inches with a right hand twist. The barrel profile is thicker than the government profile barrel but not nearly what one would call a heavy barrel. There are no step cuts. The rifle uses a mid-length gas system, which is far more ideal than the standard carbine length gas system. There is more dwell time that gives the cartridge case more time to contract down to allow for easier extraction. The Puritan barrel comes standard with E Square technology in the chamber and the muzzle is equipped with a standard A2 compensator. The T&E rifle is equipped with a mid-length Magpul MOE handguard. This is a very comfortable handguard with an excellent heat shield. The end user may install rail panels on the sides and bottom of the handguard if they wish to mount any accessory. Barrel length of the Puritan is 16.5 inches and offers in 7.25, 10.5, 14.5, 16.5 and 18.5 inches in length. According to POF, they have 20 to 30,000 rounds through the barrels and still maintain accuracy.

The gas block is billet machined from one piece of material, heat treated and nitrate treated for hardness and corrosion resistance and then case hardened to 68-70 Rockwell. First and foremost the biggest advantage of this gas block is that it is pinned in place, not held on by set screws or clamping bolts. It is very well documented that a gas block will migrate forward with heavy usage—particularly in rapid or fully automatic fire. There is a vast majority of the piston system out there with very few exceptions (Colt, LMT, LWRCI, SIG) that actually drill and pin the gas blocks in place. There is a bayonet lug and behind that is a QD sling mounting point.

The gas volume is controlled by the gas valve instead of the gas port, which will ensure constant cyclic rate throughout the life of the firearm. The gas valve is locked in place by a spring loaded pin. If the carbon build up is heavy, the face of the valve is grooved to accept a cartridge case rim to give additional leverage to remove a difficult gas valve.

Sectioned view of the POF gas system. (Courtesy of POF)

The Puritan was received with one Magpul PMag. At the time this rifle was received the new Hexmag was received as well. Hexmag was founded in 2013 and started out as a 3D design and printing of an AR-15 magazine. At that time 3D printing was quite popular. They went on to refine the design and with feedback from their local gun community they decided to move forward and produce their own magazine. In March of 2014, the company sold their first HX30-AR magazine. According to Hex mag, their “Patent Pending design provides a superior grip that is missing on other magazines. The tool-less hexagon shaped latch plate release button made a perfect platform to introduce color. The Hex ID color system was founded on the principal that gun owners purchase multiple types of ammo and like preloaded magazines. With the creation of Hexmag and the HexID System colors, all other marking methods are replaced with styling, which complements our rifles.” They offer follower and floor plates in orange, black, pink, yellow, green and blue.

For compatibility purposes, the Puritan was tested with Hexmag, PMag, Hera Arms, Lancer AWM, HK High Reliability/polymer, ASC, Surefire 60-round and standard GI magazines. There were a total of 500 rounds of Black Hills Ammunition 55gr FMJ rounds fired through the rifle for function testing – some of which were fired fully automatic. The P15 upper was placed on a LMT Guardian lower receiver. For accuracy, both Black Hills Ammunition MK262 Mod1 and Remington 77gr OTM ammunition was tested. Throughout the test there were no malfunctions of any type with any of the magazines or ammunition. The best group of the day was 10 rounds of Black Hills Ammunition 77gr OTM at 100 yards with all rounds within 1 MOA. The MSRP of the Puritan is $1,499.

The second rifle tested by SADJ was the P-308 Gen 4 rifle. These models are chambered primarily in 7.62x51mm but can also be purchased in 6.5 Creedmoor and .243 Winchester. Like the Puritan, the fit and finish is immaculate with attention to every detail. This rifle is a Gen 4, which has all the latest and best of all features offered by POF.

The POF Puritan that was sent for Test & Evaluation. Notice the mid-length Magpul MOE handguard and the standard A2-style compensator. This is POF’s entry level rifle using standard forged upper and lower receivers. Also note the Hexmag magazine that arrived at the same time as the rifles.

Beginning at the rear of the rifle, the receiver extension has a total of 7 positions for the stock to adjust. The receiver extension, which is also designed and manufactured by POF, has the anti-tilt ram on the front of the receiver extension along with the alignment tab for the buffer extension to keep the stock in the proper position. The buffer is longer than the standard carbine and is designed for use in the custom length POF receiver extension. The stock on the rifle is the Magpul STR stock.

The lower receiver is cut from a billet of 7075 T6 aluminum and has many refinements over the previous generations. There is a nice swell in front of the trigger guard to rest your trigger finger on either side of the receiver. The edges are all rounded and there is a good flare on the magazine well for loading in low level light conditions. The lower is fully ambidextrous. There is a bolt release lever above the magazine release button on the right side of the receiver and there is a magazine release lever below the bolt catch on the left side of the receiver. Also located in the receiver in front of the trigger is a bolt catch lever that can be actuated with the trigger finger just by pushing upward on the lever. There is a receiver tension adjustment screws on the top of the receiver behind the rear takedown pin. The trigger is also the POF drop in non adjustable single stage trigger. The T&E trigger broke at 5 1/4 pounds. Also included are custom-fit stainless steel KNS Precision Anti-walk Pins. The pistol grip is the Magpul MOS grip. Included is the POF ambidextrous safety as well. The trigger guard is part of the lower receiver and is oversized to accept heavy gloves. The magazine is the standard AR-10/SR-25-type magazine.

The charging handle is of POF design with knurled edges on the front and rear permitting easier and more positive grip whether you are right or left handed.

One of the newest magazines on the market is the Hexmag. The main difference between these and others are the ability to color code the follower and lock plate. The color would be visible to the shooter and that color can stand for a specific type of ammunition or a different caliber. The magazines are very well made and in the Puritan rifle worked flawlessly.

The bolt carrier is manufactured similarly to the P15. However, there are no mil-specs for the 7.62 bolt carrier group and there is no place to put the gas rings. The extractor does make use of the rubber “O” ring. The bolt is chrome plated although the bolt carrier is nickel plated. The roller cam pin is used in this model as well.

The upper receiver is manufactured from a billet of 7075 T6 aluminum. There is a forward assist and a fired cartridge case deflector. The ejection port cover also has an American Flag and says “God Bless America.”

The 7.62x51mm caliber 14.5 inch barrel is manufactured from 4150 chrome vanadium Mil-V-11595 steel and is Nitride heat treated. The rifling has 5R with 1 turn in 10 inch twist. The barrel profile is fluted to decrease weigh and increase surface area to aid in radiating heat. Pinned and welded to the barrel is a POF designed and manufactured triple port muzzle brake. The barrel nut is POF’s oversized heat sink barrel nut. The barrel nut completely encompasses the chamber and throat area of the chamber. It also supports the operating rod. The rifle uses a mid-length gas system, which is far more ideal than the standard carbine length gas system as there is more dwell time, which gives the cartridge case more time to contract down to allow for easier extraction. The Puritan barrel comes standard with E Square technology in the chamber. This rifle can be purchased with 12.5, 14.5, 16.5 and 20 inch barrel lengths.

Bolt carrier group of the Puritan. Notice the one-piece construction of the bolt carrier as well as the POF Roller Cam Pin. The bolt is a standard chrome plated bolt. The bolt carrier is NP3 coated.

The gas block is drilled and pinned in place. The handguard covers the gas block. It is Nitride heat treated.

The gas volume is controlled by the gas valve instead of the gas port, which will ensure constant cyclic rate throughout the life of the firearm. The gas valve is locked in place by a spring loaded pin. If the carbon build up is heavy the face of the valve is grooved to accept a cartridge case rim to give additional leverage to remove a difficult gas valve. The gas valve has three positions: a normal mode of fire, suppressed mode of fire and a complete
shut off position.

The handguard used is the POF Modular Railed Receiver. This is a two-piece upper receiver with a free floating monolithic rail and handguard that precisely interfaces with the POF reinforced “backbone” receiver. This takes stress away from the bolt area and eliminates flex where the operating rod, charging handle and bolt carrier sit. This not only managed the platforms points of stress but they strengthen the entire upper receiver.

The POF drop in trigger group. The KNS anti-walk pins hold the hammer and trigger pin in place.

The rifle came supplied with one Magpul PMag. At the time this rifle arrived, so did the brand new Lancer L7 AWM magazine. Just released, this is a smoke colored translucent 20-round 7.62x51mm caliber magazine. Molded into the polymer is a steel insert that wraps around the top and includes the magazine catch area. You have a metal magazine catch on the rifle that now engages a metal slot in the magazines. Molded in are two nice gripping grooves. Lancer Systems has been one of the leading high quality magazine manufacturers in the industry.

The rifle was tested with the new Lancer L7, Magpul PMag, Knight’s Armament and AASC magazines. Prior to testing this rifle, the San Bernardino Sheriff’s office had put over 35,000 rounds through their 14.5 inch selective fire P308 throughout a 17 month test and the rifle was still shooting 1.5 MOA at 500 yards. The test and evaluation P308 sent to SADJ fired over 400 rounds of Winchester USA M80 Ball ammunition with no malfunctions. Accuracy testing was done with Black Hills and Hornady ammunition. The best group achieved was with Black Hills Ammunition 7.62x51mm 175gr OTM with a group .430 inches with 3 rounds.

If you are looking for a rifle that has been fully developed and in a class of its own, POF is the rifle you want. Like all high end gear there is a high price; but you are getting something totally refined and surpasses mil-spec by light years. You truly get what you pay for.

Right side of the receivers of the P308 Gen4 rifle with the forward assist, ambidextrous bolt catch, KNS anti-walk hammer and trigger pins and the trigger finger rest divot machined into the receiver in front of the trigger. Also note the Lancer L7 translucent polymer magazine.

Left side of the POF P308 Gen 4 rifle with the newly released Lancer L7 translucent polymer magazine. Notice the ambidextrous magazine release.

The Lancer L7 magazine is based on the Lancer Advanced Warfighter Magazine. This magazine is durable and reliable – what you come to expect from Lancer. This magazine was heavily tested in the POF rifle as well as a couple others including a full auto rifle. It ran flawlessly.