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AR-15 Rifles

Review: LWRC M6-SL

by James Tarr   |  December 15th, 2011 5

The LWRC M6-SL is a piston AR and LWRC's effort to build a lighter rifle. It features a heavier H2 buffer that reduces recoil so you get back on target quicker.

Over the last few years, LWRC (Land Warfare Research Center) International has successfully established itself in the crowded AR market. It has done this by producing rifles and carbines that are well above the norm not just in quality but in performance. The only knock against LWRC guns is that they are both heavy and expensive. The new M6-SL (Stretch Lightweight) has been designed specifically to address both these factors.

LWRC’s M6 is a proven self-regulating short-stroke gas piston AR rifle, and the M6-SL Stretch Lightweight is designed to replace the base model M6. Called the Stretch because it uses a mid-length piston system, LWRC has proven that it is actually possible to make a piston-driven AR as light as a gas gun. The M6-SL weighs just 6.44 pounds empty, which is substantially lighter than most of the company’s offerings. In fact, the M6-SL is the lightest piston-driven AR I’m aware of.

LWRC M6-SL receiver

The bolt carrier and associated parts are coated with FailZero’s EXO coating, which makes the parts a snap to clean even after extended firing.

To help keep the weight down, the rifle is equipped with a 16.1-inch light-contour barrel. Many custom AR manufacturers seem wedded to the idea of heavy barrels to “ensure the utmost in accuracy during long strings of fire,” but when it comes to carbines meant for personal defense or for law enforcement, you’re simply going to run out of ammunition before you can get even a thin AR barrel hot enough to get its zero wandering. And even then, any well-made AR will still be more than accurate enough to hit human-size targets at any distance you’re likely to be engaging them in self-defense.

The M6-SL comes with Magpul MOE furniture, which is not just better designed than the mil-spec components it replaces but tougher, without adding unwanted weight. The mid-length MOE fore-end may not be as sexy-looking as the quad rail fore-ends everybody seems to be throwing on their rifles, but quad rails add weight on the front half of the gun, where you’ll notice it the most. Unless you’re active duty military you won’t need to clamp anything other than perhaps a flashlight onto the end of your rifle, so unless you can’t live without the “cool factor” of quad rails, why add all that unnecessary weight?


The M6-SL comes with a Daniel Defense rear sight mounted on the top rail.

The M6-SL comes with an enhanced Advanced Combat Bolt, which has been redesigned to improve reliability, especially extraction. The bolt, carrier, and trigger group of the M6-SL are coated with the EXO (nickel-boron) finish from FailZero. EXO is the latest wonder coating in the firearms world and works even better than you might hope. I fired close to 200 rounds through the well-lubed SL during testing, and prior to photographing the bolt and carrier all I did to clean them was wipe them with a dry paper towel. The M6-SL is provided with a small bottle of Slip2000’s EWL (Extreme Weapons Lube), which works as well or better than any other AR lube on the market.

The front of the M6-SL’s bolt carrier is stamped H2, which means it is to be used with the provided H2 recoil buffer. Heavy buffers (marked at the front with an H, H2 or H3) are designed to slow the carrier during recoil. Combined with the mid-length gas piston system, this heavier buffer helps to tame the recoil of the lightweight M6-SL. Granted, the .223/5.56 cartridge doesn’t generate a lot of recoil to begin with, but the heavier H2 buffer can get you back on target a fraction of a second quicker.

LWRC M6-SL pistol grip

The rifle features Magpul MOE furniture and ships with a 30-round Magpul PMAG.

The M6-SL comes with a fixed front sight and a Daniel Defense A1.5 rear sight clamped onto the rail. There is still plenty of real estate left on the rail if you want to attach a red dot. The rifle comes with a 30-round Magpul PMAG, the polymer AR magazine against which all others are judged.

The SL’s trigger group is standard mil-spec design, but it’s coated with EXO. AR triggers as designed are heavy and gritty, but the EXO coating made the SL’s both slightly lighter (at 5.5 pounds) and smoother. The rifle averaged better than 1.5-inch groups during accuracy testing off sandbags, but I honestly think with a match trigger it would be capable of even tighter groups.

LWRCI doesn’t seem to know how to do anything halfway, and even though the M6-SL is its “base” model, it has as many features and aftermarket accessories as some custom guns, all for a very competitive price.

Fast Specs

  • Type: piston-driven AR
  • Caliber: 5.56 NATO
  • Barrel: 16.1 in., light contour; 1: 7 twist; cold hammer-forged; /A2 flash hider
  • Overall Length: 33.7-36.7 in.
  • Weight: 6.44 lb.
  • Furniture: Magpul MOE
  • Trigger: 5.5 lb. (as tested)
  • Sights: fixed A2 front, Daniel Defense A1.5 rear
  • Price: $1,675
  • Manufacturer: LWRC International

Accuracy Results

  • Smallest avg. group: Federal 69-gr. BTHP—0.85 in.
  • Largest avg. group: Hornady 55 gr. V-Max—1.64 in.
  • Avg. of all ammo tested (5 types)—1.41
  • Accuracy results are the averages of three three-shot groups at 100 yards from a sandbag rest. Abbreviation: BTHP, boattail hollowpoint


  • NorCal Hal

    I guess I don't understand the hunting world's acceptance of the 5.56 -.223 and other small calibers for serious hunting calibers. I thought the military changed from the .30 cals to the smaller rounds because they were lighter, easier to carry more ammo, less recoil AND they wounded (incapacitated) rather than killed. I know these calibers will kill. A properly placed 22 long rifle will kill, but it seems irresponsible and very un-sportsman to TRY to kill larger than Woodchuck or Coyote size animals with these less than 65 grain bullets. I see ads promoting them for WILD HOGS which are tough animals. I have hit hogs in the front shoulder with 7 mm Rem Mags and had them get up and try to escape after a portion of the 165 granis passed through BOTH lungs. A 5.56 or 223 unless placed in the animals ear (brain shot) will wound far more animals that it will kill cleanly. I have a 243, which is a fine flat shooting caliber, but I hesitate to use it on Black Tail deer at more than 200 yards and I would NEVER use it on Mule Deer or Wild Pig, or larger, game.

  • Guest

    I'm not sure where you got the idea that the Military would choose to incapacitate an enemy with a rifle round, rather than kill. I can't imagine ANY conversation with military leaders that would endorse such an idiotic notion. As any instructor in law enforcement or use of firearms for self-defense will tell you, keep shooting until the threat is removed! Obviously, wounding someone may not remove the threat…killing always does. It's an ugly business, but war isn't meant to be a prime-time show!

    • barbarosa

      The idea behind wounding a soldier on the field rather than killing him/her is that a wounded soldier takes at least 2 additional soldier out of combat in caring for the wounded soldier. I am 61 years old, served in Vietnam and I still wonder why they gave us prairie dog rifles for combat. When “in the shit”, I NEVER used my issue rifle but ALWAYS used a captured AK. I am a living witness to seeing a 110lb NVA soldier take a central body mass shot and continued to fight as if nothing had happened. After all, the only thing that did happen was that a .22″ hole had just been punched all the way through the individual. There was virtually no blood loss and when that NVA soldier was finally killed it was after receiving multiple (as in more than 20), full auto rounds all over the little fellahs body. The 5.56 NATO round is by far one of the biggest and certainly the longest lasting mistake that our military has ever made. The rifle is overcomplicated, is prone to field failure under EVERY scenario (other than target shooting at an indoor range), and the round isn’t even the best varmint round available. Why didn’t they chamber the damned guns for the .220 Swift?

  • Emmit Straws

    not sure what norcal is talking about. last time i shot my ruger m77 in 7mm rem mag and hit a boar in its back, the thing went down and without and reflex kicking.

  • Guest

    I can shoot Moose with my 7mm Rem Mag (yeah, I have a Mossberg 4×4, it shoots true and that's what I care about), and I know for fact it is a seriously powerful round when loaded properly. The factory stuff just doesn't provide the power that you can get out of handloading. Factory is getting better, but is still vastly eclipsed by the handloads this round has to offer. That being said, 5.56 is the same way, except factory is a little better than factory 7mm. I have the weapon featured above, and it provides plenty of knockdown power for pig (unless you shoot it in the ass). Being active military, I can say that Guest after NorCal Hal is correct by stating the military DEFINITELY would rather you kill than maim if the ROE calls for it. In reality, dead people can't lie, maimed people can for propaganda purposes, and they don't come back to fight another day. 5.56 x 45mm / .223 is a round that shreds the cavity in which it enters, unless buying specific ammo to prevent that which would be used on Mule Deer / pig. My friend and I consistently knock down Mule/Blacktail Deer with his Smith M&P AR-15, and my LWRC M6 SL. Get the right round that prevents fragmentation, hit the animal in he right spot, and it will go down.

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