LWRC NEXT-GEN ARs

The R.E.P.R. features a FAL-style charging handle on the left…

The R.E.P.R. features a FAL-style charging handle on the left side of the receiver.

Direct gas impingement (DGI) operating systems are not unique to the AR-15, but have been associated with the gun since it was adopted as the M16 by the U.S. military in the mid-twentieth century. Properly maintained and lubricated, a DGI AR-15 will run well for a very long time with few, if any malfunctions. Contrary to what many believe it is reliable, but it does require much more lubrication of the bolt carrier group than that required of a piston operated firearm.

A DGI gun bleeds hot combustion gasses from the barrel and vectors them via a gas tube into the receiver, where they impart energy to the bolt carrier group to cycle the gun. Those gasses deposit carbon and unburned powder residue into the operating parts where, unless a great deal of lubrication is present to keep the particles suspended, they cause friction which eventually binds the system. Heat deposited into the receiver also increases stress and reduces the service life of components. All of this requires more frequent cleaning and maintenance, and dusty environments like those encountered in the mid-east make it necessary to clean the gun even more frequently.

Gas Piston
Recognizing all this, many AR-15 manufacturers have recently introduced gas piston operated AR-15-style guns that have less intense maintenance and lubrication requirements than DGI guns. One company that has been producing piston guns for longer than many is LWRC International of Cambridge, Maryland. The company was founded with the intent of developing and perfecting a short stroke gas piston system for the AR-15 and began offering them in 2004.

LWRC offers several black guns, and each one is characterized by the company’s proprietary gas piston system. One unusual characteristic of the system is the segmented piston rod rather than the one-piece piston rod design that is so common on other guns. Darren Mellors, LWRC’s Executive Vice President, explained that one of the challenges in developing a reliable piston system was the difficulty in machining a long, thin, one-piece piston rod to proper tolerances and then correctly heat-treating it so that it would not eventually bend and cause a stoppage. To solve the problem, LWRC developed the segmented piston that consists of a piston cup that fits over the gas plug, an operating rod that contacts the bolt carrier and an intermediate rod that connects them. The design allows a bit of play which reduces the possibility that the rod will bend and stop the show which in a self defense or battle situation could be catastrophic.

According to Mellors, during tests the LWRC piston system ran without maintenance or cleaning for the entire service life of the test weapon with no failures and no build-up of carbon. He explained that the design of the piston cup and gas plug permits the cup to scrape itself clean and expel carbon into the atmosphere with each stroke.As the piston assembly moves to the rear about six-tenths of an inch, the operating rod strikes a thrust shoulder that is machined into the bolt carrier. It has been found that a bolt-on thrust shoulder that replaces the gas key is prone to failure, so LWRC decided to use a thrust shoulder integral to the bolt carrier. Another problem with piston guns is carrier tilt where the bolt carrier’s body tends to tilt downward at the rear because of the off-center thrust of the piston. This tilt tends to wear the lower receiver and buffer tube unevenly, which can eventually cause a failure. To remedy this, LWRC made the outside rear diameter of the carrier larger and machined skids at the bottom to more evenly distribute friction over a wider surface and reduce wear. The sides of the bolt carrier are also partially faceted instead of round in order to give any debris that might get into the receiver a place to accumulate instead of causing a stoppage. Lastly, the bolt carrier has a nickel-boron coating to increase lubricity and resist corrosion, and although the bolt appears similar to that of a standard AR-15, it is made of a material used in NASCAR transmissions and is much stronger.

Load Comments
  • RAIDER ROB

    BEST AR IN THE WORLD!!!! I OWN AN LWRC M6SL AND IT IS BY FAR, THE BEST ASSAULT RIFLE ON THE MARKET. IT IS FLAWLESS AT 500 YARDS AND HAD NO PROBLEM HITTING ANYTHING AT 800 YARDS. ITS LIKE HAVING A CQB TYPE WEAPON WITH THE ADVERSITY OF SHOOTING ACCURATELY AT LONG RANGE. HAVE TO TEST IT OUT AT 1000 YARDS, BUT I DONT THINK I WILL BE DISSAPOINTED. SPEND THE EXTRA CASH AND GET AN AWESOME PEACEKEEPER. :-D:-D

  • Excedrine

    I’d say .5-.75 MOA is plenty accurate for a battle rifle, as you can expect with a REPR, and they’re a helluva more reliable than ANY DGI gun – including any offering from Lanner Tactical.

    LWRC knows how to build guns.

  • uk sniper

    Because they are not very accurate! :-/
    Check out http://www.lannertactical.com for the best guns about… I have seen their Raven in action… These guys know how to build a gun 🙂

  • Lynn Gifford

    Why don’t I find any articles on the accuracy of the REPR?? Where are the articles on something at 100 yards, and also 200/300 yards????