Defense Media Network

SAW “Lite”

New Weapon and Ammo Weight Reduction Efforts

The U.S. Army’s Armament Development and Engineering Center (ARDEC), located a Picatinny Arsenal, N.J., is highlighting a weight reduction exploration on a prototype modified M249 Squad Automatic Weapon and prototype ammunition that has the potential of cutting the soldier weight burden in half.

“The Army has been concerned about reducing soldier load for years – this isn’t a new problem,” said Kori Phillips, an ARDEC systems management engineer. “We’ve really put an emphasis on it with this project; there was a great motivation for reducing weight.”

According to representatives at the center, the ARDEC team is nearing the final stages of designing and testing a lightweight SAW that fires cased telescoped ammunition (CTA). CTA ammunition, which replaces the traditional brass shell with a thin plastic casing, weighs 40 percent less than traditional designs.

“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.”

Claiming additional reliability improvements based on a rotating chamber design, he added, “We’ve avoided the common problem of failure to feed and failure to eject. In the current SAW system, that’s where you primarily have failures and malfunctions.”

New ammunition being developed by the Armament Research, Development and Engineering Center includes caseless telescoped ammunition (front row) and cased telescoped ammunition (back row). Both rounds are nearly 50 percent lighter than their standard 5.56 mm brass-shell counterparts. ARDEC photo.

“It has a unique chamber design. The cartridge goes straight through from feed to eject,” Phillips explained. “With a regular SAW, or M249, the chamber and barrel is one piece. But in this new light machine gun, the chamber rotates back and forth. The system works in a cyclical pattern, so you’re not interfering with your own system.”

According to a Picatinny release, the prototype lightweight SAW system has been under development for the last six years and is ready to hit the range for a military utility assessment next summer at Fort Benning, Ga.

“So far, the ARDEC team, along with contractor AAI Corporation, has built three lightweight SAWs and has test-fired more than 10,000 rounds of cased telescoped ammunition,” it reads. “They plan to build seven more guns and produce 100,000 more rounds in time for the utility assessment.”

When loaded with 600 rounds of cased telescoped ammo, the new SAW system will be 16 pounds lighter than a traditional SAW loaded with the same amount of standard, brass-cased ammo.

“ARDEC is also developing a lightweight rifle that fires cased telescoped ammunition. This rifle is the same overall weight and length as a standard M4, but because of the modified design, there is a four-inch gain in barrel length,” the release adds.

When loaded with cased telescoped ammo, that system weighs 40 percent less than an M4 loaded with standard ammo.

A soldier test fires a prototype cased telescoped light machine gun. Currently under design by the Armament Research, Development and Engineering Center, this weapon system weighs 42 percent less than the standard M249. ARDEC photo.

Picatinny sources add that ARDEC is also developing “even lighter ammunition that promises to cut weight by 50 percent and reduce volume by 40 percent, called caseless telescoped ammunition. This round features a solid propellant body that burns completely when the round is fired. Essentially, the case itself is the fuel. With caseless ammo, there is no need for the weapon to eject a case after firing, which virtually eliminates weapon lock-up.”

“There is so much more to consider when developing caseless ammunition,” Phillips said. “We are currently redesigning it for cost purposes, but obviously our primary concerns are the ballistics, the reliability and the repeatability.”

The team has built one caseless telescoped weapon and shot about 500 caseless rounds, but they have since had to go back and alter the design.

While the Picatinny spotlight presents the technology in a positive light, it should be noted that CTA technology is not without its critics, who point to more than five decades of technology exploration without fully fielded results. Some early examples of that criticism, which date back to the mid-1990s, along with resulting DoD findings, can be seen at:


Scott Gourley is a former U.S. Army officer and the author of more than 1,500...