POF-USA/Vltor P-416 Assault Rifle
It has been almost a year and a half since the original tests, and a review of the data we collected from those outings created a few additional questions that needed to be answered. We noticed that the running temperatures of the POF P-416 Assault Rifle were consistently lower than those taken during the same circumstances with a direct gas impingement system. It makes perfect sense that the absence of the gas tube redirecting hot gasses into the action would relate to lower operating temperatures but we wanted to find out exactly how much of a difference it would actually make, especially during abnormally heavy usage. This allowed us to set up and began phase II.
Phase II would be another type of endurance test where large amounts of ammo would be fired, in very long, continuous and uninterrupted bursts, possibly bringing the test rifles to the point of catastrophic failure. Upon reaching the predetermined number of rounds, the temperature of the rifle would be measured in several areas, and the testing would immediately continue, allowing for the residual operating temperatures to continue to increase. No cooling time would be allowed.
Since BETA C-Mags are readily available and have worked well for us in past testing of this type, we decided to use them as the baseline and go with 100-round continuous mag dumps. We determined that the complete test would consist of 1,000 rounds, barring any type of system failure. After continuously firing
each 100-round burst, the surface temperature would be measured on the following parts: the bolt face, the chamber area, the gas block and the muzzle brake. The surface temperature of the barrel would be measured occasionally but was not considered a vital measurement for purposes of these tests. The temperatures
would be measured in the Fahrenheit scale with a Geneva Scientific Model TLL950LS Infrared thermometer. This thermometer has a working temperature range from -32° up to +950° and no contact is necessary to slow down the testing or require cumbersome embedded sensors.
Since we determined that it was going to be possible to reach a catastrophic failure point, for safety purposes, each test rifle was fitted with a KNS precision tripod adapter allowing it to be fired from a standard MG42 anti-aircraft tripod, and both series of tests also employed a set of KNS Precision Spade grips. This combination would allow the shooter to place his body well behind the action of the firearm and not require a cheek weld on the stock only inches from the chamber.
Noted firearms expert and gunsmith Charlie Cutshaw took a POF-USA P-416 assault rifle chambered for 6.5mm Grendel and modified it using a Vltor VIS (Versatile Interface Structure) kit for the upper receiver, along with a Vltor Rifle Modstock. Then Cutshaw added some other extras, such as a Vltor top mounted bipod, attached to the top of the handguard. The trigger group is match-quality. The rifle uses an 18.5-inch match-quality tipped with a Vltor VC-65 flash suppressor/brake. The handguards have four-point MIL-STD-1913 rails, and the upper receiver has its own MIL-STD-1913 rail. The receiver rail is topped with a Leupold Mk 4 1.5-5x20mmMR/T telescopic sight, and the upper handguard rail uses an AN/PVS-22 UNS (Universal Night Sight), a 3rd-Generation night vision scope.
Since early 2006, a few variants from the POF-USA P-416 family have quite steadily become standard
equipment when going to the shooting range. After an in-depth article and the initial endurance testing of
the 9.25-inch version this system became a curiosity that people started regularly asking about. As of this writing, the 9.25-inch version has fired well in excess of 20,000 rounds and continues to run excellent to this day. The initial test allowed us to shoot over 9,000 rounds without cleaning or adding any lubrication and we strongly believe that had it not been for a magazine malfunction, the testing could have continued much further.
The two can be used together day or night since the AN/PVS-22 has a day and a night channel. On the lower rail is a SureFire M-900 Foregrip WeaponLight with an IR filter attached to allow night use without showing a bright visible light source. It also includes a vertical foregrip behind the light. (The SureFire M-900 is required since the AN/PVS-22 needs a light source to function.) Charlie Cutshaw’s conversion job is based on the semiautomatic P-415; simply use only the semiautomatic figures for this version.