LWRC M6

The M6 is a series of carbines designed and manufactured by Land Warfare Resources Corporation. It is based on the M4 carbine, with which it shares 80% of its parts. The 'M' model name is not a US military designation. Like the HK416, it features a proprietary short-stroke self-regulating gas piston system and bolt carrier/carrier key design, which prevents trapped gases from contacting the bolt carrier or receiver of the weapon, which reduces the heating and carbon fouling of the internals, simplifies field maintenance, and improves reliability.

Standard length barrel is 16.1 in, with a 1/7 in twist (six lands, right twist) barrel with a ferritic nitrocarburized surface conversion which covers the barrel, inside and out, as well as the piston components. Barrel lengths of 10.5", 12.7", 14.7" and 18" (available for select models) are available.

The Discovery Channel show Future Weapons featured the M6A2 and the M6A4. Additionally, the weapon was featured on the Spike TV show Deadliest Warrior, in the episode "SWAT versus GSG-9", as the main carbine for the SWAT team.

M6
The M6 is LWRC's most basic model. It is the most similar to the M4, but it still has the short-stroke gas piston system common to all LWRC's models. The M6 lacks a rail system and instead uses a variation of the hemispherical polymer handguards found on almost all stock M4 clones.

The M6 has now been replaced by the M6-SL (stretch lightweight) as LWRC's most basic offering.

M6A1
The M6A1 is also similar to the M4, but is designed to accept SOPMOD accessories similar to the M4A1 used by USSOCOM. The difference between the M6 and the A1 model is the addition of a rail system

M6A2
The M6A2 is identified by LWRC as its "standard carbine" and has features that allow it to be used in multiple roles in addition to an assault rifle, such as an optional longer barrel allowing it to be used as a designated marksman rifle. It is an approved personal purchase duty carbine of the United States Drug Enforcement Administration in a special configuration called the M6A2 D-DEA, however, it is not standard issue. All A2 series use flip up iron sights mounted to their Mil Std 1913 style rail interface as the A2 series lacks a built in sighting systems like those found on the A1 and A3 models.

Personal Security Detachment
The PSD is an ultra short barrel carbine with an 8 in barrel and Magpul CTR stock. Derived from the M6A2 Carbine it comes chambered in 5.56 mm or 6.8 SPC. It is also available without a stock as the M6A2-P Pistol but is semi-automatic and also chambered in 5.56 mm and 6.8 Remington SPC.

M6A3
The M6A3 is designed specifically to be a designated marksman rifle. This rifle uses a midlength short stroke gas piston system to reduce recoil and increases the speed of follow up shots. It features an adjustable gas system to allow the user to adapt the rifle to different conditions and is designed to accommodate optics such as scopes and reflex sights. The A3 integrates a gas block using a flip up front sight as opposed to the fixed AR series sight of the M6 and M6A1.

M6A4
The M6A4 is designed to fulfill the role of the squad automatic weapon. It was developed for the United States Marine Corps' Infantry Automatic Rifle program, which sought to replace some M249s with a more maneuverable weapon. However, it was not accepted for final testing in favor of a Heckler & Koch HK416 variant.

Externally identical to the M6A3, it fires from a closed bolt during semi-automatic fire, and from an open bolt during automatic fire which is labeled as "OBA" for Open Bolt Automatic. While in OBA mode, the first round may be fired from a closed bolt (it will then lock back and subsequent shots will be from an open bolt until the operator manually closes the bolt again). Firing from an open bolt increases cooling and eliminates the potential for accidental discharges due to rounds "cooking off" in an overheated chamber. It also allows for a faster rate of fire. However an open bolt design means that the first round fired will have reduced accuracy when compared to a closed bolt design. This is due to the fact that when the trigger is pulled, the bolt slams forward under spring tension, stripping a round from the feeding device, chambering it, then firing it. This sequence of events shakes the firearm and takes longer than a closed bolt design to fire the first round (greater lock time). This also introduces extra potential points of failure in the ignition of the first round.

M6 Individual Carbine
Developed for the Aborted US Army individual Carbine Competition the Individual carbine is a 5.56x45 mm weapons system. First batch units used a spirally fluted barrel in either 14.7 inches or 16.1 inches later units returned to a more conventional style. The front Gas block differs from other M6 series via a bayonet mounting gas block with flip up Iron sight, sub variant of the IC the Individual carbine the IC-SPR uses a low profile gas block. The system uses a Monolithic rail system that is forged as part of the Upper receiver. IC comes standard with a Magpul MOE pistol grip, and either a Magpul stock or a proprietary compact stock  the M6-IC was not down selected as part of the competition.

Six8
The Six8 is a derivative of the M6 series with variants conforming to the M6A2, M6A2 SPR and PSD but engineered specifically around the 6.8x43 mm SPCII round. LWRCI partnered with ATK and Magpul to develop the Six8 to fulfill a large overseas military contract. ATK developed the contract ammunition, a 90 grain Gold Dot round optimized for short barreled rifles. Magpul created a larger variation of their PMAG Magazine, called the "Black Widow" with a blood red follower for the 6.8 mm round. The upper and lower receivers are developed specifically to fit this Magpul magazine and optimized around the 6.8x43 mm round. The flagship model of the Six8 series is the UCIW which features a 8.5 inch barrel. The A2 and SPR variations feature longer barrel lengths including 12.7 inches, 14.7 inches and 16.1 inches. Weapons of this series come standard with Magpul MOE pistol grips, and LWRCI proprietary compact stocks and iron sights.