By Christopher R. Bartocci
The industry has seen much change over the last 10 to 15 years in caliber as well as weapon revivals. In the mid 1950s the AR-10 was placed on the Ordnance Corps scrap heap with all the other excellent ideas that were not invented by the Army. The 5.56mm cartridge entered the scene during the Vietnam War and set the course for the next 50+ years. Gene Stoner never gave up on his scrapped AR-10 and then in the early 1990s teamed up with C. Reed Knight Jr. at Knight’s Armament Company and brought back his AR-10 as the SR-25. Unfortunately, Gene Stoner would not live to see his AR-10/SR-25 succeed to equip the most elite units of the U.S. military as well as it being type classified as the M110.
As the debate started in the early 2000s, the direct gas versus piston debate heated leading several companies to introduce piston operated 5.56mm rifles. One of the pioneers was LWRC, Inc. (LWRCI) who was primarily a research and development company. In 2008, essentially all assets of LWRC Inc. were bought by Richard Bernstein whom is well known on the Eastern Shore of Maryland for his many companies which are all defense related. This includes L3’s BAI Aerosystems, and Matech, Inc. LWRCI has had their weapons in the field for refinement and fine-tuning for more than a decade. But that was 5.56mm and 6.8mm SPC. LWRCI has picked up the torch, gone into full fledged manufacturing, and has expanded their line of products to include a 7.62mm rifle that has taken many years to design and refine. Initially the project was spurred by the promise of an open competition by the U.S. Marine Corps for a new semiautomatic sniper rifle, but to date, that has not surfaced.
The REPR (Rapid Engagement Precision Rifle) is a 7.62mm rifle that utilizes the LWRCI short stroke tappet piston system. Like other piston-operated rifles, the REPR uses a free-floating configurable handguard/rail system. One of the common criticisms of piston systems is that the operating rod is attached to the barrel assembly/gas block, which in many designs affects the natural harmonics of the barrel. Now how much that affects accuracy with the REPR will have to be seen at the range. LWRCI’s reason for utilizing the piston system not only revolved around their mantra of a cleaner, cooler more reliable operating system, but they felt it was essential to provide reliability with the shorter barreled versions of the REPR. The barrels can be had in 12-inch (light), 16-inch (light and heavy), 18-inch (heavy) and 20 inches (heavy). Depending on the need, you can have a lightweight carbine, a battle rifle or a sniper rifle configuration.
The REPR system was designed around the needs of a Special Operations Sniper/Assaulter. Sniper/Assaulters deploy with their Special Operations Assaulter teams taking down high value targets be they buildings, encampments or vehicles. Typically the Sniper/Assaulter provides infiltration cover, exfiltration cover and security for the team and target area. To date, the Sniper Assaulters have used either the venerable SR-25 or M110. Most carry a primary weapon as well - typically an M4 or a 10.3-inch barreled MK18 Mod0 5.56mm Carbine. They do this because the M110 and its mounted optic are not ideal for the job of clearing buildings, alleys, and rooms to get to their overwatch position. Sniper rifles usually have long heavy barrels making the system difficult to operate through tight quarters. This is exaggerated when a sound suppressor is in place making the system even longer.
LWRCI envisioned a system that takes advantage of the modularity of the Stoner design. Just push two pins to change the upper, and you have a completely different tool for the job at hand, complete with zeroed optics appropriate for the mission. With the REPR, the Sniper/Assaulter carries one primary weapon, one caliber of ammunition, and does not have to carry two types of magazines. A typical load out might be a 12 inch Assaulter REPR upper with an Aimpoint or EOTech 1X sight. On his back in a courier type tactical case a 20-inch complete with magnified illuminated optics. The 12.7-inch is short enough for CQB, even with a sound suppressor in place and is effective to 400 meters. Once in overwatch position, the upper can be changed out in 20 seconds extending the effective range of the Sniper/Assaulter to 800 meters. The short stroke gas piston allows the uppers to be swapped without changing the buffer or buffer spring ensuring the gun is reliable regardless of what size upper is used. LWRCI claimed they were looking for a rifle that acted like a sniper rifle, but was required to have the durability and reliability of an assault rifle.
One such technology was the adoption of a precision manufactured cold rotary hammer forged barrel. This is a solid departure from most of the other precision semi-auto rifles manufactured in North America. Hammer forging is much more common in Europe, and has not yet been accepted here in anything other than machine guns or assault rifles. Colt Canada (formerly Diemaco) has been using the process since the mid1980s in their C7 and C8 series rifles and carbines. Hammer forging forms the cold metal over a precision mandrel that has the reverse image of the rifling by use of high tonnage rotary hammers. The rifling is imprinted into the bore much like the heads and tails image of a coin is imprinted from a die under high pressure. This work hardens the steel and gives the barrel a much longer service life.
Generally, sniper rifle barrels are unlined precision cut rifled barrels in stainless steel alloy to ensure consistency and precision of the rifling. This provides an accurate barrel, but with one major trade off: life expectancy. A good stainless cut barrel may only last 2,000 rounds before the accuracy degrades. This would not be acceptable for LWRCI’s REPR due to its dual role as a battle rifle. LWRCI knew the major factors in accuracy are consistency of the bore diameter; lack of took marks or chatter in the bore, concentricity of the bore to the outside diameter of the barrel, a perfect crown, clean consistent rifling, concentricity of the chamber to the bore, and lack of structural stresses that might be present in the barrel. Their hammer forging process and finish machining create a very clean barrel devoid of the accuracy robbing problems stated above. Plating the bore with chrome does protect the bore but it is inconsistent in its application, and ruins the work you did to perfect the bore. Instead of plating the barrel with chrome, they developed a process they call NiCorr. NiCorr converts the surface of the material - case hardening it to a depth of 0.005 inch and turning it a lustrous black. They do this inside and out of the barrel. The black finish is from carbon being brought to the surface of the material in the NiCorr process. This same process is used to extend the life and sharpness of metal cutting and machining tools. The barrels are submerged and treated in molten salts followed by a quench and polish process. The temperature of the process is regulated to ensure the case hardening of the barrel while at the same time stress relieving the barrel. Just like heating up a spring until it is no longer springy, the stress relief process prevents the barrel from wanting to shift in one direction when firing the weapon and heating up the barrel. LWRCI claims NiCorr is harder than chrome, has a lower co-efficient of friction, more resistant to heat and does not interfere with the previous work of creating a perfect bore.
Historically the U.S. military would never accept an M16/M4 barrel that was hammer forged even when Colt offered. The U.S. government believes the sharpness of the leading edge of the lands cannot be duplicated in a hammer forge and that the sharp leading edge was critical to accuracy. Some claim the hammer forged barrels last longer and others say the button cut barrel is more accurate. This debate will reconvene for me on the range and be settled one way or another. As there are several technologies present here I have not seen used in combination, I will let the performance of the rifle decide.
LWRCI claims they configured their rifle to meet the requirements of its intended mission and make it as comfortable and ergonomic as possible. They threw out the traditional top rear mounted T shaped charging handle common to Stoner rifles in place of a left side mounted non-reciprocating charging handle with integral forward assist. The reasons cited were three fold. The users required the ability to operate the charging handle without breaking their cheek weld or eyes on target through the optic. If the weapon were to malfunction after a miss, or fail to fire, the valuable seconds required to clear or re-charge the weapon and regain your target in the reticle could be the difference between mission success and failure. They also have a gas shut off on their gas regulator allowing the use of the rifle and charging handle as a straight pull bolt gun. If a sniper was taking a long shot and did not want to leave brass on the battlefield, or when employing subsonic ammunition and a suppressor might prompt its use as a straight pull bolt gun to ensure elimination of any noise from the action. Since Sniper/Assaulters would run the REPR, there is a good chance a sound suppressor would be in use much of the time. The top-charging handle of the Stoner rifles allows a space for gas to escape directly into the shooters face when a suppressor is used. The side charger allowed LWRCI to close off this gap and eliminate AR gas to the eye altogether.
The side charger along with other minor configuration differences took some getting used to, but once it took it was clear LWRCI was on to something. The side charger was easier to manipulate than the standard. Eye relief requirements of powerful optics often cause the optic to overhang the top-charging handle of the M110 making the charging handle difficult to manipulate. LWRCI’s left sided charging handle fixes that annoyance as well. The handle has a forward bolt assist built into it eliminating the right side AR button style forward assist. Pulling back the handle, pressing the handle inward toward the receiver engages the bolt carrier allowing it to be forced forward and closed. The charging handle configuration has also changed the practicality of other operating controls like the bolt catch. Yes, there is still a standard bolt catch in the standard location, but they added another bolt catch to the right side operated by the trigger finger. This makes engaging and releasing the bolt catch very fluid while manipulating the charging handle.
When LWRCI started the REPR project, they went through several iterations; the first being the SABR, or Sniper Assaulter Battle Rifle. They felt the SABR needed to lose some weight, improve in the ergonomics department, and had to be user configurable. They also sought to strengthen and elongate the interface between the barrel and the receiver to limit flex between these assemblies. The stiffer interface would also limit some of the point of impact shift that can occur when a sound suppressor is installed. The threaded front receiver extension was extended almost twice the size that of an AR-10 pattern. They created a new barrel nut that was also very long, and pulled double duty as the handguard/rail mount providing perfect alignment with the receiver. The rail itself is a free float design with a removable top with an integral Mil-Std-1913 rail that is designed to allow access to the piston system and return to zero once reinstalled. The 3, 6, and 9 o’clock rails are user configurable. You only need to install the length of rail you need in a particular location for the accessory you need. This makes the handguard/rail very comfortable, low profile, and cuts unneeded weight.
LWRCI uses an interference fit between the barrel extension and the receiver. Cold, these parts do not fit. To install the barrel, the receiver must first be heated expanding the orifice, the barrel inserted, then it cools and contracts for the interference fit. Under use, this is one of the hottest parts of the weapon, which causes the same expansion. It makes sense to fit these parts while hot. Then they use a lock nut that allows them to put a very precise torque on the barrel. LWRCI felt the current semi-auto sniper rifles were just scaled up AR-15 type rifles with heavy barrels and believes these details have been overlooked when you consider the mission, the accessories, and the user. Getting to some of the mechanics of the rifle, the operating system is made up of the gas block, regulator, piston cup, intermediate rod, operating rod and operating rod spring. The regulator has four positions: an off position making the rifle a single shot, one for suppressed fire, a normal setting and an adverse conditions setting. Disassembly of the operating system is done by removing the top rail of the handguard. Unscrewing the two locking screws located on the face of the end of the handguard and lifting the top rail off is all that is required to accomplish this. With the bolt carrier removed, pull rearward on the intermediate rod and remove the piston cup. Then remove the intermediate rod followed by the operating rod. Simply reverse the process to reassemble the operating system.
LWRC has evolved their 5.56mm bolt carrier over the years and many of those changes were incorporated into their REPR. LWRCI basically scaled up their latest iteration of the 5.56mm bolt carrier group but removed the forward assist notches and added the grooved to the left side of the carrier where the cocking handle will engage. The bolt and carrier are coated with a proprietary Nickel Boron coating that is superior to the previous DuPont Teflon, and Nickel Teflon used. They also coat the barrel extension, the bolt, and the cam pin. Unlike previous 5.56mm iteration carriers, the impact key is not a separate component - it is now machined into the carrier increasing the strength. The bolt carrier also incorporates sand cuts on the running surfaces of the bolt carrier. These simply allow a place for sand and dirt to reside without causing interference to the bolt carrier.
The lower receiver is manufactured from a billet and accepts an SR-25-type detachable box magazine with a capacity of 5, 10 and 20 rounds. KAC, C-Products, Magpul LR20 Mag and DPMS magazines are all compatible for this rifle. The REPR was provided with C-Products 10-round magazines. Acquired for testing were 20-round C-Products magazines as well as the newly introduced Magpul PMag 20LR Mag. The selector lever settings are in the popular pictogram form and have a witness notch on the right side of the selector as well as selector settings on the right side allowing a left handed shooter to know the condition the rifle is in. The stock may either be fixed or retractable. The sample rifle was set up for a sniper rifle and was equipped with the MagPul PRS stock that is adjustable for length as well as cheek weld. The PRS stock is a little on the heavy side but in this authors experience is the finest precision stock for any black rifle. On the heavy barrel sniper variant of the REPR, the PRS’ weight balances the rifle. The lower was also equipped with a Magpul MIAD pistol grip and enhanced trigger guard. LWRCI has teamed with Magpul on all of their weapon systems and use Magpul’s stocks, pistol grips, trigger guards and magazines. The trigger used is manufactured by Geissele Automatics and is adjustable or fixed determined by the model. The sample rifle was equipped with the adjustable trigger that was a two-stage configuration which was very comfortable and smooth to pull. A good trigger is critical on a sniper rifle or any rifle for that matter. Another very innovative feature of the REPR is the ability to tighten the upper receiver so there is no play between the upper and lower receivers. Under the pistol grip is a screw that is tightened by the operator to the desired tension. This ensures a lifetime tight fit regardless to wear on the pushpin holes of the receiver and eliminates the requirement for aftermarket wedge devices.
Both detachable front and rear sights were provided on the sample rifle. The folding front sight attaches directly to the handguard/rail rather than the barrel. It has ears to protect the post and is activated and deactivated by a spring loaded lock. The rear is similar in that it is engaged and disengaged by a spring loaded pin. The rear sight is adjustable for windage only and the front for elevation only. Both sights provided were manufactured by Troy Industries with the LWRCI logo on them.
The cycle of operation of the REPR is as follows: The trigger is pulled releasing the hammer which in turn strikes the firing pin. The firing pin strikes the primer detonating the cartridge sending the bullet down the barrel. Once the bullet reaches the gas port, gas is bled into the regulator. Depending on the setting, the valve regulates the amount of gas that enters the nozzle. The gas chamber/expansion chamber is created between the inside of the nozzle and the piston cup. The piston cup, which is attached to the intermediate rod, pushes rearward on the operating rod which is spring loaded. The operating rod strikes the top of the bolt carrier driving it rearward with a hammer like-blow. As the bolt carrier moves rearward the operating rod spring returns the operating rod, intermediate rod and piston cup back into battery on the gas block. The bolt unlocks and extracts and ejects the fired cartridge case. The buffer/action spring move the bolt carrier group forward stripping a round from the magazine feeding and chambering the round and finally the bolt locks ready for the next shot. Excess gas is bled out of the gas block between the nozzle and the piston cup; therefore no gas enters the bolt carrier group keeping the bolt carrier group clean and cool.
Overall the weapon was extremely impressive. The fit and finish was superb. Every attention to detail was paid and the best choices for the stock and pistol grip were made in my opinion. If this was my rifle these would be the exact accessories I would add. There were no machining scuffs or nicks on the rifle and the anodizing matched on the upper and lower receivers.
Testing was conducted using Silver State Armory (SSA) ammunition. SSA is known for manufacturing some of the highest quality duty and match ammunition in the industry at competitive pricing. Silver State Armory just moved to a state-of-the-art facility in Packwood, Washington where they have a 100 meter underground range and the facility meets United States Department of Defense requirements to manufacture military contract ammunition. They manufacture their own brass. All SSA ammunition is loaded with custom blends of powder geared towards the specific loading. They offer several loadings in 5.56mm, 7.62mm NATO, 6.8SPC and .499 LWRC. They are also one of the only ammunition manufacturers in the United States to manufacture armor piercing rifle ammunition in 5.56mm, 7.62mm NATO and 6.8SPC.
Function testing was done with their 150gr Nosler Accubond cartridge (SSA10084-N150). Approximately 200 rounds were fired for function testing with no malfunctions. Now is the opportunity to see if a hammer forged barrel and a piston have much effect on accuracy in a precision rifle. This load shot consistently just under 1 MOA at 100 yards. For accuracy the Silver State Armory 168gr Sierra OTM was used (SSA10084-OTM). This round consistently shot between 1/2 to 3/4 MOA at 100 yards. The accuracy of the REPR will challenge any bolt action sniper rifle on the market today as well as any other semi-auto out there. The combination of a premium quality barrel, match grade ammunition and an excellent trigger produced respectable groups by any sniper’s standards. Recoil was quite moderate for a semi-auto rifle. Engagement and follow-up shots were quick and accurate, which are the attributes that expand the capability and role of a sniper armed with a semi-auto. I suppose this ends some of the debates I mentioned earlier, however, it is my belief from looking at the multiple design and technology changes LWRCI has made that no one feature is singularly responsible for this performance. It is the proper combination of these design features and technologies working together as a system. This includes the ammunition.
The REPR has undoubtedly added to LWRCI’s opportunities to compete in both the U.S. and international markets on both 5.56mm and 7.62mm rifles. The REPR could be used as a police sniper rifle, competition rifle, military rifle or sporting rifle. It is just that versatile. It comes in carbine and rifle configurations and will serve any need that come up where 7.62mm firepower is needed. The REPR is already in service with the Drug Enforcement Administration F.A.S.T. (Foreign-deployed Advisory and Support Teams) as well as the DEA’s Office of Global Enforcement in Afghanistan and other less than friendly parts of the globe. These are being used in the Sniper/Assaulter role described previously as the teams generally helo insert to a target compound, clear it of bad guys, then take up sniper overwatch security duties while other members of the team or USSOCOM conduct their mission of searching for and destroying drug and weapon caches. The predecessor to the REPR, the SABR are employed by the Pentagon Force Protection Emergency Response teams and can been seen daily in the overwatch positions facing the entrances to the Pentagon. Internationally, LWRCI is has agreed to team with the King Abdullah II Design and Development Bureau to co-manufacture rifles in Jordan for use by the Jordanian Special Forces and Sniper Battalion.
This article first appeared in Small Arms Review V14N5 (February 2011) |
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