Review: POF ReVolt Straight-Pull AR
July 15, 2016
It's been close to 120 years since an infantry rifle with a straight-pull action has been introduced. Add to that the rather odd concept of a "rule-beater," and you have all the makings for something unusual and, yes, innovative.
First, let's try to define the firearms industry term "rule beater." Put simply, these are firearms designed to circumvent legislation. One of the most current examples would be the faux short-barreled rifle with the SIG Sauer-type brace substituting for a buttstock.
During the era of the infamous assault rifle ban, 1994 to 2004, we had handguns with the grip frame reduced to accept the mandatory 10-round magazine. Prior to the 1990s, there were Ruger Mini-14 rifles chambered for the .222 Rem. cartridge to beat Italian and French legislation prohibiting civilian ownership of firearms chambered for so-called military calibers.
The 9x21mm cartridge is another example of this, as was the Colt M1911 chambered for the .30 Luger (7.65mm) round. Farther back in history, there were .25 ACP vest pocket pistols with 6-inch barrels designed to go around regulations in a number of Central European countries.
Today, we have the poor wretches forced to live in the People's Republic of California, and for them, we have the almost insane "bullet button" magazine catch/release and Frankenstein monster AR buttstocks. Troy Industries, Inc. is marketing a pump-action AR-15 for anti-gun nations like New York and Connecticut.
Let's dart backward very briefly and look at the two major straight-pull rifles from the 19th century. This type of rifle can appear intimidating to the uninitiated, as at first glance it may appear that, unlike a bolt-action rifle, there is nothing to prevent the bolt of a straight-pull rifle from flying rearward and imbedding itself right between your eyes. Nothing could be farther from the truth.
Lt. Col. Eduard Rubin, director of the Swiss Federal Ammunition Factory and Research Center at Thun, presented his 7.5x53mm cartridge to the Swiss military authorities in 1883. It was one of the first smallbore, high-velocity military rifle cartridges. It had what was at that time a unique projectile with a lead core enclosed within a copper alloy jacket. It eventually evolved into the slightly longer 7.5x55mm Schmidt-Rubin cartridge.
During the same time frame, Col. Rudolf Schmidt, Director of the Swiss Federal Arsenal at Bern, after studying every contemporary rifle design, developed a straight-pull concept that was adopted in 1889.
There were numerous models of the Schmidt-Rubin series, including the shorter action Model 1889/96, the single-shot Model 1897 Cadet Rifle, the Models 1900 and 1900/11 Short Rifles, the Models 1905 and 1905/11 Carbines and the Model 1896/11, which led directly to the seminal Model 1911 Rifle (the early rifles were in caliber 7.5x53mm Swiss and the later models from the M1911 forward were chambered for the 7.5x55mm Swiss round). This is a complex design and requires a detailed technical explanation that is quite beyond the scope of this article.
But, explained simply, when the bolt handle is pulled rearward, and when the operating rod's backward travel continues, its pull stud is forced to move in a straight line, as its rib is moving in a slot between the two parallel cylinders bored in the receiver.
When the pull stud comes out of the straight cut in the bolt-locking sleeve and hits the curved portion, it generates a cam action that forces the locking sleeve to rotate. As a consequence, the two locking lugs on the sleeve are rotated out of their recesses in the receiver, and move into the diagonal grooves that connect the locking recesses with the longitudinal lug travel grooves. While complicated, it's perfectly safe.
The Austrian Model 1895 rifle is chambered for the Austro-Hungarian 8x50R cartridge and was also a straight-pull type with Mannlicher design magazines. The bolt head has two opposed cam-shaped locking lugs, which engage in seats in the receiver ring. This is also a perfectly safe system and was later upgraded for the very powerful 8x56mm cartridge.
Now, let us fly back to the future. Frank DeSomma of POF-USA has personally designed an incredibly innovative straight-pull rifle, completely on his own, without prior knowledge of either the Schmidt-Rubin or Mannlicher rifles. In fact, when I mentioned them, he told me that he had never even heard of them. The end result was the POF ReVolt.
POF-USA has taken its standard AR lower receiver and attached it (permanently if intended for sale in states like New York or Connecticut) to a unique upper receiver. Simply put, the bolt carrier has been modified. The primary alteration consists of a longitudinal slot milled directly in back of the "key" on top of the bolt carrier.
Into this slot is placed an oval-shaped projection on the bilateral straight-pull cocking handle. Since the gas piston operating system has been completely deleted, the key no longer serves a purpose and thus becomes a vestigial piece.
The eight-lug (seven of which are actually used for locking) Stoner-type, cam-operated bolt holds the system in battery and in this instance is spring-loaded within the bolt carrier.
As no gas, via either a short-stroke piston or impinging gas tube, provides inertia to propel the bolt and carrier rearward, this function is performed manually by retracting the bilateral bolt handle rearward.
When the bolt handle is pulled rearward and rotates the bolt head 22 ½ degrees clockwise by means of its cam slot on top of the carrier, the bolt carrier can be fully disengaged from the barrel's extension. One of the most outstanding proprietary features of the POF ReVolt rifles series is the bolt carrier's patented roller cam pin, which completely eliminates excessive wear on the upper receiver as the bolt group reciprocates.
Retraction of the bolt handles is both completely silent (a potentially important attribute for clandestine sniping operations) and exceptionally easy. This latter is a direct function of POF's unique E-Square Dual Extraction Technology Chamber.
In essence, this consists of four equidistant small square channels in the neck of the chamber. These provide the same ease of extraction provided by the fluted chambers of the Heckler & Koch half-locked roller action, used at one time on its rifles and submachine guns.
The upper and lower receivers, bolt carriers, bilateral cocking handle's shafts and unique roller cam pins of the ReVolt Light and Heavy have NP3 plating.
This process, an exclusive coating of the Robar Companies, Inc., is a surface treatment for metals and metal alloys that provides the appearance of satin electroless nickel by combining sub-micron particles of PTFE (polytetrafluoroethylene, i.e., Teflon) with autocatalytically applied nickel/phosphorus.
The result is a very accurate, dry-lubricated, low-friction surface that is extremely resistant to wear. As the PTFE is evenly distributed and locked into the nickel/phosphorous matrix, when wear occurs, fresh particles of PTFE are exposed to keep the surface lubricated. NP3 has a high lubricity and low friction coefficient.
No lubricants are required on any metal surface so treated, and powder residue and carbon fouling can be easily removed with a dry cloth. NP3 has a non-reflective satin gray appearance.
The new straight-pull POF ReVolt from POF-USA is available in two models. The caliber 5.56x45mm NATO version (Model PN:00759 and UPC: 847313007599) is called the POF ReVolt L (Light) and the caliber 7.62x51mm NATO variant (Model PN:00765 and UPC: 847313007650) has been designated as the POF ReVolt H (Heavy).
Specimens of each were sent to Firearms News for test and evaluation.
The POF ReVolt Light and Heavy weigh 8.3 pounds (3.76kg) and 9.5 pounds (4.3kg), empty, with an overall length of 38.5 inches (977.9mm) and 40 inches (1,016mm), respectively. Complete with one 10-round MagPul magazine, hard case and factory manual, the manufacturers suggested retail price of the ReVolt Light is $2,029.99 and the ReVolt Heavy is $2,679.99.
The POF ReVolt L and H have Rock Creek 5R, 4150 MIL-B-11595, chrome-moly vanadium alloy steel 18.5-inch (470mm) barrels (machine gun rated) with five grooves and a 1:8 left-hand twist in caliber 5.56x45mm NATO and in caliber 7.62x51mm NATO the barrel is V button-rifled with five polygonal grooves and hand lapped with a 1:10 right-hand twist.
These twist rates are an excellent compromise for accurately accommodating a substantial range of projectile weights.
Starting with a Rockwell C hardness of 28-32, after heat-treating the barrel, hardness is 70 Rockwell C in 5.56mm and 68 Rockwell C in 7.62mm. The barrels have a black nitride finish.
The barrel is fluted to reduce weight, increase strength, increase the surface area for improved heat dispersion and because it looks good. The surface area of the fluted 5.56mm barrel is 51.139 square inches, compared to 47.635 square inches for a standard M16A2 M4 barrel.
The bore is corrosion resistant and 10 times thicker and harder than MilSpec chrome lining. The barrel extension is machined from high-grade steel and heat treated for an increase in strength of more than 30 percent over existing MilSpec and features an enhanced feed ramp to increase feeding reliability. The POF ReVolt Light barrel has 1/2 x28 muzzle threads and the POF ReVolt Heavy is equipped with 5/8x24 muzzle threads.
The barrel is press-fit, rather than slip-fit, to the upper receiver, as this provides a more positive lock between these two components. As the method of operation is by manual straight-pull, the bolt has no gas valves (or rings) as found on the M16/AR-15 series. These gas valves must be frequently replaced, as they quite literally burn up. The bolt head is made from Carpenter 158 and the carrier from 8620 steel. Both are carburize heat treated as per MilSpec.
Another especially unique feature of the POF ReVolt and other POF-USA rifles is the heat sink barrel nut, which dissipates heat away from the critical throat, upper receiver, bolt and bolt carrier areas and increases the rifle's service life.
This heat sink barrel nut, acting as an extension of the receiver, increases the upper receiver's overall strength and diminishes flex. For example, POF's 5.56x45mm heat sink barrel nut has a total surface area of 50.973 square inches. Compare this to the 8.565 square inch area of a standard M16A2 M4 barrel nut.
The MIL-STD-1913 rail interfaces attached to the 14.5-inch POF-USA Free Floating Monolithic M Rail forearms (which are M-Lok compatible) on these rifles are minimal, as is the current trend on AR-type rifles. At 12 o'clock there is a 9-inch MIL-STD-1913 rail interface on top of the upper receiver and another 2.5-inch rail interface at the front end of the forearm for attachment of a front BUIS.
There is another short rail interface at 6 o'clock at the front of the forearm for attaching a bipod or similar accessory. The forearm is machined from 6061 T6 aluminum alloy that has been hardcoat black anodized.
The POF-USA Triple Port Muzzle Brake installed on the POF Revolt L and H is just that: a muzzle brake, not a flash suppressor. As a consequence of the laws of Newtonian physics, devices attached to the muzzle end of a rifle barrel invariably are successful in addressing only one parameter.
The POF ReVolt brake, a proprietary design, has three oval-shaped ports on both the right and left sides, at 3 and 9 o'clock. There are no ports at the 6 o'clock underside position. At the top of the brake, at about 1 o'clock, there are three circular ports and a single circular port at approximately 11 o'clock.
There are five impact tips at the front of the brake. The effect of this port geometry is as follows.
The flash signature is significant and comes principally from the oval ports on each side of the brake. But the size and character of a rifle's flash signature is principally a function of the cartridge's propellant, not any type of device attached to the muzzle.
Muzzle jump and the recoil impulse of the POF ReVolt L and H are both almost imperceptible and completely controlled, permitting extremely fast target reacquisition after each shot. As a consequence of this brake, the now mostly imperceptible recoil impulse becomes a completely linear vector in parallel to the barrel's axis.
With muzzle devices you must select whether you want to diminish the flash signature or the recoil impulse and muzzle jump. You cannot have your cake and eat it too. The brake is machined from 4140 chrome moly steel and nitride heat-treated. A jam nut instead of washers was used to attach the muzzle brake to the barrel, as it's easier to install in this manner and puts less stress on the barrel.
The upper receiver of the POF ReVolt has some of the usual obligatory M16/AR-15 features, such as a spring-loaded dust cover over the ejection port, and an M16A2-type empty case deflector immediately to the rear of the ejection port. However, the mostly useless "forward bolt assist" has been deleted as it would serve even less purpose on a manually operated, locked-breech rifle.
In states other than those where the upper and lower receivers must be permanently attached to each by the front receiver retaining pin, the upper receiver can be easily exchanged for a POF-USA semiautomatic short-stroke piston operated receiver.
The POF ReVolt L and H lower receivers are machined from 7075 aircraft-grade aluminum alloy billet stock. The POF ReVolt L and H lower receivers' magazine wells are both enlarged and flared to facilitate installation of magazines under high-stress environments.
The trigger guards are enhanced by enlargement and, in my opinion, strengthened significantly by its one-piece configuration. They're large enough to permit the use of gloves without the necessity of a hinged bottom, which structurally weakens that area of the lower receiver.
The selector levers, magazine catch/releases and the retracted-bolt-release controls are all bilateral, with appropriate controls on each side of the lower receiver.
The company installed the excellent Magpul MOE pistol grip on the POF ReVolt. This ergonomic, hand-filling design combines aggressive texturing with storage capability. The one-piece reinforced polymer construction provides simplicity while still maintaining the durability needed to withstand operational environments. The MOE grip accepts optional storage cores for gear storage and includes a basic grip cap.
A substantial number of people now use Magpul magazines almost exclusively. The polymer M16/AR-15 magazines manufactured by Magpul Industries Corporation are every bit as rugged and reliable as those of the Kalashnikov series and maybe even more so.
Available in either black, green or flat dark earth in 10-, 20-, or 30-round capacity, Magpul magazines feature a four-way, anti-tilt follower that enhances feeding reliability, a constant internal curve for consistent round stack regardless of round count, a true 10-, 20-, or 30-round capacity that eliminates the need to download, and a floorplate design that aids in magazine extraction from pouches and eases disassembly.
These magazines can, of course, be installed in the correct caliber in either the POF ReVolt Light or Heavy. However, since it's a rule breaker, the rifles are provided with black 10-round MagPul polymer magazines.
All of POF's rifles are continually evolving, as important proprietary innovations are added, without fanfare and sometimes unnoticed by the less observant. An example is POF's EFP (Enhanced Finger Placement) single-stage trigger. Its front face design naturally guides the tip of the trigger finger to the lowest point on the trigger for a consistent and crisp single-stage let-off.
While factory specified to be 4 pounds, the trigger pull weight of our test specimen POF ReVolt Light was a superb 3.0 pounds and a slightly heavier 3.75 pounds on our Revolt Heavy; maybe these are too light for some, but they are perfect for me.
POF also uses an anti-walk bar on each side of the trigger's axis pin to prevent it from migrating out of the lower receiver, something you won't find on most ARs.
Both the POF ReVolt Light and Heavy come equipped with the really clever and innovative LUTH-AR Modular Buttstock Assembly (MBA). Its cheekpiece can be extended up or down in height by 1 inch and the length of pull (distance from the rear surface of the buttpad to the front face of the trigger) can be adjusted by 1 1/16 inches.
At approximately half the weight of comparable adjustable buttstocks, the LUTH-AR MBA weighs only 1.2 pounds. Manufactured from strong glass-filled nylon, it's completely bilateral, as the cheekpiece can be installed for either right- or left-handed shooters. Its overall length is 10.375 inches collapsed and 11.5 inches when fully extended.
The POF Revolt Light and Heavy rifles are equipped with a standard AR buffer and recoil spring assembly, although in this case, they serve little purpose other than absorbing the rearward manual thrust of bolt carrier assembly.
The chance of a high quality scope's failure on an operation is statistically quite low. Nevertheless, they can fail, and emergency iron sights are absolutely essential on any rifle deployed in warfare.
Designers and manufacturers of cutting edge optical mounting systems and tactical accessories, GG&G are suppliers to law enforcement agencies throughout the United Sates and U.S. military units of all branches. Simply put, its product line is often incredibly innovative and always outstanding in quality.
From the wide array of rear sights available from GG&G, we selected its very popular MAD (Multiple Aperture Device) Back Up Iron Sight (BUIS) (#GGG-1006). A very low profile folding rear sight, it clears most optics.
Its salient feature is four apertures of two different diameters on the same plane, which means they are zeroed to the same point of impact. Thus, rotating the knurled aperture disc in either direction will bring the next size in view. The small aperture is .073 of an inch in diameter and the large aperture is .199 of an inch.
The standard military windage knob and screw are used. One click of the windage knob provides about .65 moa adjustment. The MAD mount body is CNC-manufactured from billet 6061 T6 aluminum alloy and Type III hard-coat black anodized.
The black manganese-phosphated stem and aperture disc are made from billet 4140 ordnance steel and have hardened wear points for long service life. Once in the up position, a spring lock prevents the sight from accidentally lowering. Developed to fulfill a request from Naval Surface Warfare and used extensively by Coalition Forces in the Middle East, the superb MAD BUIS sells for $140.
This has been mated with a flip-up front sight for tactical forearms (#GGG-1033). Just pull up and this front sight can be deployed on target. Once deployed, it locks solidly into the upright position. It cannot be folded down without depressing the actuator button on the right side.
It can be easily co-witnessed with red dot optics and it uses standard military sight components. It has been manufactured from 6061-T6 aluminum, bead-blasted, dehorned for the operator's safety, and Type III hard coat anodized with a non-reflective, corrosion-resistant, matte black MilSpec finish.
The price is $89.95 and an optional Trijicon tritium front sight post can be ordered for an additional $50. (The same feature is available for the MAD BUIS rear sight for an additional $50 as well.)
Test, Evaluation and Conclusions
The Nightforce B.E.A.S.T. 5-25x56 F1 scope was used for all accuracy testing off the bench with both the POF ReVolt Light and Heavy.
The wind velocities encountered during this test and evaluation of the POF ReVolt L and H using the Nightforce B.E.A.S.T. were unusually calm for the high altitude location normally used for our accuracy testing.
The winds were gusting with a low of 4.5 mph. The other atmospheric conditions were a humidity of 10.5 percent, which is normal for the Lower Sonoran Desert, and an ambient temperature of 74.5 degrees F. The winds were blowing, as usual, from WNW (277 degrees to 295 degrees). The elevation at the test site is 3,626 a.s.l. (above sea level).
First on deck was the POF ReVolt Heavy, and four different loads were tested with this rifle and the Nightforce 5-25x56mm B.E.A.S.T., firing from a benchrest at 100 meters. We commenced our test using ammunition from Hornady Mfg. Co.
Hornady developed its .308 Winchester 178-grain BTHP (Boattail Hollow Point) Superformance Match (catalog No. 8077, lot No. 3121176) for those who must stretch 7.62x51mm rifles out to the greatest effective range possible for this caliber with, in addition, reduced wind drift. This bullet leaves a 24-inch barrel at 2775 fps, which is up to 200 fps faster than any conventional ammunition in this caliber. We also used Hornady's match load with a 168-grain BTHP bullet.
In addition we tested two different loads of Australian Outback ammunition in caliber .308 Winchester. The two loads sent to us for test and evaluation were loaded with the following projectiles: the 165-grain Sierra SBT GameKing, with a muzzle velocity of 2839 fps, is a boattail design intended for long range hunting; and the 168-grain Sierra HPBT (Hollow Point Boattail), with a muzzle velocity of 2755 fps, is most often used for competition shooting.
As expected these manually operated, straight-pull actions have a greater accuracy potential than their semiautomatic equivalents. The Hornady 178-grain BTHP Superformance Match round produced a group dispersion of .5 moa fired off the bench at 100 meters. The Hornady match ammunition with a 168-grain BTHP projectile shot to .45 moa. The Australian Outback loads performed as follows: the 165-grain Sierra SBT GameKing produced .35 moa and 168-grain Sierra HPBT .5 moa.
The accuracy tests of the POF ReVolt Light were conducted with ammunition from Hornady and Black Hills Ammunition. Hornady Mfg. Co. provided two types of its highly regarded TAP (Tactical Application Police) ammunition with 60-grain and 75-grain bullets.
Hornady's TAP (Tactical Application Police) ammunition is not only capable of match-grade accuracy, it was specifically designed for law enforcement and personal defense applications. Unlike non-expanding military issue small arms ammunition, Hornady TAP features expanding projectiles.
Black Hills Ammunition provided its highly regarded 77-grain Match Boattail Hollow Point (BTHP) load that uses a Sierra MatchKing bullet.
At 100 meters, the Black Hills 77-grain Match Boattail Hollow Point (BTHP) load repeatedly shot groups at .5 moa and under. Hornady's 60-grain TAP ammunition produced .6 moa groups. The 75-grain Hornady TAP FPD (For Personal Defense) load has an excellent reputation for performance with 16-inch barrels. It did not disappoint and produced outstanding accuracy at .4 moa. It remains my favorite load for this rifle.
Nothing unexpected here with either rifle, as any manually-operated turn-bolt or straight-pull action of high quality should be able to outperform a rifle with a semiautomatic action. Both the POF ReVolt Light and Heavy operate silently and manipulate with ease and are a pleasure to shoot.