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 scraped AR-10 and then in the early 1990s teamed up with C. Reed Knight Jr. at Knight’s Armament Company and brought back his scrapped 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 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.