A Different Stroke

LWRCI Goes From Piston Perfection To Direct Gas
Impingement With Its M6IC-DI 5.56 Carbine.

By Holt Bodinson

LWRC International really perfected the self-regulating, short-stroke piston AR. Today they offer three outstanding high-end, piston-driven AR families in 6.8 SPC and 7.62 NATO as well as in 5.56 NATO.

Based in Cambridge, Maryland, the company has earned a solid reputation for upgrading the stock AR platform and taking it to a new level of accuracy and reliability using enhanced components of advanced design and special metal treatments.

So it came as a surprise when LWRCI recently launched an addition to their M6IC (“Individual Carbine”) family based on Eugene Stoner’s original Direct Gas Impingement operating system (although Stoner never described it in those terms).

I suspect we’ll never see the end of the argument over which system is better. There are certainly strong adherents on both sides of the issue. It reminds me of the debate between those who promote the single-action automatic pistol and those who firmly believe the double-action auto is intrinsically better.

Both the DGI and the piston-driven supporters have their strong points. The DGI folks argue their system is mechanically simpler, lighter and more reliable with fewer moving parts generating fewer vibrations, hence intrinsically more accurate and less expensive to build. The piston clan maintains their system runs cooler—especially on full-auto—and doesn’t coat the guts of the gun with carbon fouling, and is thus more reliable.

Personally, I run both systems with complete satisfaction and see no difference between them in terms of accuracy. When it comes to cleaning though, the piston supporters win that argument hands down. However, modern metal finishes on components like the bolt and bolt carrier and synthetic lubricants have made carbon removal easier than it’s ever been.

Designated the “M6IC-DI,” the new model is available in both 5.56 and .300 Blackout. It’s a cool-looking carbine, but to really begin to appreciate what LWRC builds into their rifles, you have to look at the details of each component (and most of those details are common across all LWRC product lines).


Running the M6IC-DI with an extended grip on the
handguard is easy with the integrated hand stops


LWRCI’s new DGI carbine employs proprietary components and
metal treatments, just like the company’s well-regarded
piston guns.

Parts, Particulars, Components

The first component that immediately caught my eye was LWRCI’s wild, spiral fluted barrel. They’re hammer-forged from a 41V45 alloy right at the factory. Why fluted? The spiral flutes reduce barrel weight by approximately 20 percent over an equivalent diameter barrel, and with the greater exposed surface area, cooling is enhanced. In 5.56, LWRCI uses a 1:7-inch twist, which can handle bullet weights ranging from 50 to 80 grains.

After hammer forging, the bore is NiCorr treated (Ferritic Nitrocarburizing—an advanced form of case hardening) which, according to LWRCI, “is more lubricious, harder wearing and more heat and corrosion resistant than hard chrome.” Starting off with a denser, hammer-forged bore surface to begin with—and then treating it with NiCorr—should ensure prolonged barrel life. The muzzle end of the barrel is threaded 1/2×28, a good standard thread for flash hiders and suppressors. Interestingly, the barrel extension is secured to the upper with a non-indexing torque ring rather than a barrel nut, which according to LWRCA, “provides even, full circumferential pressure on the barrel extension for absolute optimal fit and function.”

Next I discovered it wasn’t the upper that intrigued me, it was the lower. All the controls are completely ambidextrous. Looking at the right side of the lower and then at the left side, you realize the bolt catch and release, the magazine release and the selector switch can be readily operated from either side of the gun. I like the concept, except for the 2-position (safe/semi-automatic) selector switch.

To begin with, the switch is too small to be easily “thumbed.” I’m right-handed, so in the carry position my trigger finger is extended above the trigger well on the right side. When on “Safe,” the selector switch on the right side is touching—and parallel to—my trigger finger. When I thumb the selector switch to “Fire” from the left side, the rotating selector switch on the right side immediately comes into contact with the flesh of my extended trigger finger. That level of interference is not good when you’re trying to quickly transition from “Safe” to “Fire.” Wearing gloves exacerbates the problem. It would be better if the selector switch were reversible—not ambidextrous.


The controls of the M6IC-DI carbine are completely ambidextrous.


Opening up the M6IC-DI, you’ll find a bolt carrier like none you’ve ever seen. The carrier key is machined integral with the carrier, not bolted on and staked. It’s an example of LWRCI’s excellent engineering. The bolt carrier, cam pin and some fire control system parts are nickel-boron coated, providing permanent lubricity, corrosion and wear resistance. This slick finish also doesn’t hold carbon. I might also add LWRCI uses a chrome silicon buffer spring for extended spring life.

Measured on my Lyman scale, the trigger pull averaged 6.5 pounds. The reset is short and crisp. Just aft of the trigger well and below the rear takedown pin is a small screw-adjustable pad putting upward pressure on the upper as it’s seated. Nice touch. The pistol grip by Magpul is rubber wrapped, providing excellent control while the compact, 6-position buttstock is a proprietary design by LWRCI. Finally, the triggerguard is oversized and well shaped to accommodate gloved hands.

The forged upper sports an integral Picatinny rail as does the 11-inch free-floating quad-rail handguard, factory fitted with LWRCI rail skins and hand stops.

Weighing 5-3/4 pounds without sights, the M6IC-DI is a nicely balanced, smooth swinging, compact package and about a 1-1/4 pounds lighter than LWRCI’s M6IC piston-driven model.

Mounting a Burris 3-9x40mm tactical scope on the M6IC-DI, I was anxious to see how the new carbine would feed, function and group. The feeding, firing, extracting and ejecting cycles went off without a hitch. The M6IC-DI proved itself to be a MOA carbine with a refined taste for 77-grain match bullets. As I’ve reported previously, the velocity of 2,399 fps for the Federal match load is not a misprint or chronograph error even though the company lists the velocity as 2,720 fps. It’s slow but is it ever accurate!

One of the nice qualities of proprietary firearms is the company is in complete charge of the design, manufacturing and quality control processes. Their firearms are not a mixed bag of somebody else’s parts. Being able to substitute a torque ring for a conventional barrel nut or making the carrier key an integral part of the bolt carrier or giving the bore a NiCorr treatment is the company’s choice and totally within the company’s control. The end product is usually superior in its details. LWRCI’s new M6IC-DI fits that description perfectly.

Maker: LWRC International
LLC, Cambridge, Maryland
(410) 901-1348,

Action Type: Gas-operated semi-automatic, Caliber: 5.56 NATO (tested), .300 AAC Blackout, Capacity: 30, Barrel length: 16 inches, Overall length: 32 to 35 inches, 6-position stock, Weight: 5-3/4 pounds, Finish: Black, Sights: None (full-length Picatinny rail), Stock: LWRCI buttstock and quad rail handguard, (Magpul MOE+ grip), Price: $1,599

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