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Piston Performer

Piston Performer

LWRC's M6A2 is a refined, short-stroke gas-piston AR.

LWRC's M6A2 is a good-looking, reliable and accurate gas-piston AR that handles well up close yet can reach out for those long shots.

In the last few years, the AR market has become flooded with offerings. A bewildering array of one-man shops and large companies (including big "traditional" gun companies such as S&W, Remington and Ruger) offer almost every conceivable manner of AR.

Because of the mind-numbing number of models now available, I have become somewhat jaded. However, I must say that I was pleasantly surprised when I recently opened a box from LWRC International. Inside was a handsome carbine that actually managed to stand out from the AR crowd.

For those of you unfamiliar with LWRC International, the Cambridge, Maryland, company has grown to become a firm with three facilities with a whopping 250,000 square feet of space and more than 50 CNC machine centers, robotic welding, laser cutting and screw machines along with mil-spec painting capability.

Unlike other companies, its focus has been steadfastly fixed upon the development of a reliable short-stroke gas piston-operated version of the AR-15. Over the years, it has continually refined and improved its designs and today has more experience with gas-piston ARs than almost anyone.

The result of this work is a patented self-regulating short-stroke, gas-piston system utilized in the M6 family of rifles and carbines. I tested the M6A2, which you may recall graced the cover of the July/August 2009 Rifle Shooter.

I was impressed by the obvious attention to detail in both its manufacture and assembly. The polishing on the upper and lower receivers was a noticeable step above the norm, and the anodizing was flawless. This gun is a head-turner.


The rifle is offered in two calibers--5.56x45 NATO or the hard-hitting 6.8mm SPC--and in four barrel lengths: 10.5 and 12.7 (both restricted), 14.7 and 16.1 inches.

The heart of the M6A2 is an upper receiver that is fitted with a mid-length free-floating rail system. Mated to the upper is a match-grade, cold rotary hammer-forged medium-weight barrel made from 41V45 steel.

The barrel is finished, internally and externally, in NiCorr for corrosion resistance and long service life. LWRC claims this finish outperforms traditional chrome plating and provides a useful barrel life of approximately 20,000 rounds.

The barrel sports a target crown and is fitted with an A2 flash suppressor and a low-profile gas block. The receiver is finished in a proprietary nickel coating that the company says provides a hard, permanent lubrication to moving parts.

The lower is fairly standard but fitted with a heavier H2 buffer. The carbine is nicely dressed with Troy back-up iron sights, a Vltor E-MOD stock and Magpul MIAD grip.

And that's just the beginning. Neatly hidden beneath the removable upper handguard is a short-stroke gas-piston system the company describes as lightweight, self-regulating and self-scraping.

While gas-piston systems are hardly new to the AR (Taiwan has issued gas-piston ARs since the 1970s), in recent years they have become popular in here. Why? Although the standard Stoner direct-gas system is well-proven and reliable, like any other system it is less than perfect.

A gas-piston system addresses some of the criticisms leveled against Stoner's design--namely that a great deal of heat and fouling are injected into the bolt carrier. In addition, carbines with very short barrels often lack the reliability of a full-length rifle--especially when a sound suppressor is mounted

But there is no free ride. A piston system not only introduces more parts into the equation, it also pushes the bolt carrier to the rear in a manner different than Stoner intended. This latter issue gives rise to a phenomenon referred to as carrier tilt. When the piston impacts the carrier, the front of the carrier lifts and rotates slightly as it moves to the rear. LWRC addresses this problem with a redesigned bolt carrier.

If not properly set up, a piston system can also negatively affect the barrel's harmonics and accuracy, especially on a light barrel. So the longer a company has been building piston guns the better.

My test rifle was fitted with a 14.7-inch barrel with a permanently attached flash suppressor to bring it out to the legal length. Chambered for 5.56x45 NATO, it was rifled with a 1:7 inch RH twist.

It weighed in at a handy seven pounds. Overall length is 35.2 inches with the stock extended and 32 inches when collapsed. During testing I mounted a Burris 3-9x40 TAC-30 for precision work and an Aimpoint Micro T-1 in a LaRue Tactical mount for everything else.

After zeroing, I checked the M6A2's accuracy from the bench at 100 yards. I utilized three loads for this portion of testing: Black Hills' 77-grain Mk262 Mod 1, Federal's American Eagle 62-grain FMJ and Wolf Performance Ammunition's 75-grain steel-case HPBT.

While all three loads shot quite well, Black Hills' military match load turned in the best performance, as you might expect. It posted a respectable 1.2 inches at 2,618 fps. With a better trigger I'm sure I could have shaved a bit off this. Before removing the Burris, I put the M6A2 to work on steel from 100 to 600 yards. Here it proved capable of consistently hitting a six-inch plate at 300 yards and an 11.5x20-inch LaRue Sniper target at 500 yards.

Switching to the Aimpoint, I ran the M6A2 through a variety of drills from two to 100 yards. Here the LWRC proved quick handling and easy to hit with. I did note the recoil impulse is different than a direct-gas gun. Not bad, just different.

Reliability was flawless, despite being fed a large quantity of steel-case Wolf. No problems of any kind were encountered; the LWRC simply chugged away. After numerous 30-round magazine dumps, the fore-end became almost too hot to hold, but the bolt carrier remained cool to the touch.

I checked the action and found it to be almost as clean as when I started, although some fouling vented from the system accumulated on the objective lens of the optic.

All in all, I was impressed by LWRC's M6A2. It's a good-looking piece that performed well. If a piston gun interests you, this is one to consider. It's expensive at $2,200, but if you have the means, an LWRC would be a nice addition to anyone's AR collection.

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