Soldiers may soon have lighter machine gun

By Eric Kowal, RDECOMJuly 21, 2011

Soldiers may soon have lighter machine gun
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Soldiers may soon have lighter machine gun
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PICATINNY ARSENAL, N.J. (Army News Service, July 15, 2011) -- Any Soldier who has ever served as a squad automatic weapon gunner is resigned to the burden of lugging a heavy weapon and ammunition on patrol.

Soldiers may soon have a solution, however, one that cuts the weight of small-arms ammunition nearly in half and provides a potential replacement for the SAW that weighs a whopping 8.3 pounds less than the current M249.

The weight reduction comes in the form of a new light machine gun and ammunition developed by engineers from the Lightweight Small Arms Technologies program, or LSAT.

The program is managed by the Joint Service Small Arms Program, which is part of the Armament Research, Development and Engineering Center at Picatinny Arsenal.

“LSAT is all about reducing Soldier load,” said Maj. Matt Bowler, a military adviser to the small arms program.

“We know that the Soldier is overburdened,” he continued. “The Soldier carries too much weight so anything we can do to reduce Soldier load increases the Soldier’s effectiveness, his capability on the battlefield and his survivability.”

The weight reduction provided by the LSAT will have a significant impact for the SAW gunner, the most heavily burdened Soldier in the squad.

According to a study conducted in 2005, the average fighting load for the SAW gunner is 79 pounds. That is nearly twice the weight a Soldier should carry, according to Army doctrine.

Excess weight significantly affects the speed of maneuver of the SAW gunner and therefore the entire squad, which relies on suppressive fire from the SAW gunner to support its movement.

So how is such a tremendous weight reduction achieved?

“We are using cased telescoped ammunition which uses a strong plastic case instead of a traditional brass case,” said Kori Phillips, a systems management engineer with ARDEC.

Weight reduction for the weapon was achieved by designing the new weapon platform using the latest materials technologies as well as modeling and simulation to achieve minimal weight without compromising performance.

With a basic load of 1,000 rounds, the LSAT light machine gun and its cased telescoped ammunition is 20.4 pounds lighter than a traditional SAW with the same amount of standard, brass-cased ammunition.

To try out the new lightweight ammunition and machine gun, a small group of Soldiers and members of the Army and Navy Senior Executive Service attended a live-fire demonstration in June at the Marine Corps Base in Quantico, Va.

One Soldier who appreciated the lack of brass during the live-fire demonstration was Maj. Gen. Nick Justice, commanding general of the U.S. Army Research, Development and Engineering Command.

“I’m used to getting hot brass in my face since I am left handed,” Justice said.

The Army’s chief scientist, Scott Fish, also attended the demonstration and tested the weapon first-hand. He later said he was extremely impressed and eager to learn more about the system.

As chief scientist, Fish identifies and analyzes technical issues and brings them to the attention of Army leaders. Additionally, he interacts with operational commanders, combatant commands, acquisition, and science and technology communities to address cross-organizational technical issues and solutions.

Sgt. Jason Reed of the Soldier System Center in Natick, Mass., demonstrated firing both the LSAT LMG and the SAW from various positions -- from prone to kneeling to standing while in full combat protective equipment.

“The difference between the two weapons is night and day,” Reed said.

Before his assignment with Natick, Reed was assigned to 2nd Battalion, 325th Airborne Infantry Regiment in the 82nd Airborne Division and carried the SAW as an Automatic Rifleman for a total of two years, including a deployment to Iraq.

“The main thing I would take away from this is the weight issue, especially when firing in the standing position,” Reed said. “Bringing up the SAW, especially if you have it up for a long duration of time, it starts to get the best of you and you have less accuracy on target.”

Despite the significantly reduced weight of the LSAT LMG and its ammo, there is no degradation in accuracy or lethality.

“The cased telescoped ammo still provides the same muzzle velocity, range and accuracy as the brass-cased ammo,” Phillips said. “We’re not sacrificing lethality for weight. The plastic case does the same job.”

In addition to significant weight savings, the LSAT is designed to provide other advantages over the current SAW. With a rotating chamber design, the cased telescoped light machine gun improves reliability.

“We’ve avoided the common problem of failure to feed and failure to eject,” Phillips said. “In the current SAW system, that’s one of the places where you primarily have failures and malfunctions.”

The chamber is unique in that the cartridge goes straight through from feed to eject.

“With a regular SAW, or M249, the chamber and barrel is one piece,” Phillips explained. “But in this new light machine gun, the chamber rotates back and forth. The system works in a cyclical pattern, so there’s no interference.”

Additionally, the rotating-chamber design provides better heat management. Combined with the insulating properties of the plastic ammo cases the LSAT LMG has potential to decrease the possibility of a cook-off or eliminate them altogether.

Another significant feature is the long-stroke, soft-recoil design, which provides a noticeable reduction in felt recoil over the current SAW. This significantly increases control, thus providing the shooter the ability to put more rounds on target and making the weapon much easier to fire from the standing position as a result of decreased muzzle rise.

Moreover, the LSAT LMG has one other unique feature that the current SAW lacks: the ability to switch to a semi-automatic mode. This feature increases the flexibility of the weapon, allows for the precise engagement of point targets, and helps to conserve ammunition in situations where full-automatic fire may not be necessary or desired.

In September, the weapon and ammunition will undergo a Military Utility Assessment that is intended to demonstrate the advantages that the LSAT LMG provides for the warfighter, as well as possibly influence the user community to develop a Capability Development Document, or CDD.

A CDD is required before the system can transition to a program of record and enter the engineering and manufacturing development phase.

That is a significant milestone. It has taken six years to get from a concept to a fully functioning weapon that is ready to be evaluated by Soldiers.

Thus far, the ARDEC team, along with prime contractor AAI Corporation, has built four light machine guns and has test-fired more than 12,000 rounds of cased telescoped ammunition. They plan to have a total of eight weapons and produce more than 100,000 rounds in time for the assessment.

The LSAT development is much broader than just a new light machine gun. It is applicable to a broad range of calibers and platforms to include a carbine that also fires the lightweight cased telescoped ammunition.

The carbine is the same overall weight and length as the standard M4, but with its modified design, there is more than a one-inch gain in barrel length, which provides a slight increase in muzzle velocity over the current M4 Carbine.

Also under development is a caseless variant of the ammunition that provides a slightly greater weight savings and a significant decrease in volume, providing a 50 percent reduction in weight and a 40 percent reduction in volume compared to current brass.

A video of the live-fire demonstration can be seen on the Picatinny Arsenal YouTube channel at

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