The Army Research Laboratory is developing a "third arm" passive mechanical appendage that could lessen Soldier burden and increase lethality. Weighing less than 4 pounds, the device attaches to a Soldier's protective vest and holds their weapon, putting less weight on their arms and freeing up their hands to do other tasks. (Photo Credit: Courtesy photo)

U.S. troops in Vietnam lugged 85 pounds or more – from their weapons and ammunition to survival gear to survive the harsh environment. But that load has only grown, and now the high-tech soldiers of Afghanistan and Iraq haul more than 100 pounds. More weight is expected to be added in the future to the already heavy burden on the back and shoulders of American warriors.

But the military is now developing a new passive “third arm” attached to soldiers that would allow them to carry more, and perhaps even have better marksmanship, according to the Army News Service.

“It is not a product – it is simply a way to study how far we can push the ballistic performance of future weapons without increasing soldier burden,” said Zac Wingard, mechanical engineer at the Army Research Laboratory.

The arm is made of carbon-fiber composite, and is expected to shift the weight of weaponry from the arms to the body itself.

The arm is expected to be able to be used while the soldier is prone, or on either side of the body.

Potential tactical uses include firing around corners with augmented reality displays, keeping a rifle handy while operating a power saw during breaching operations, or even having a soldier lead a team into a room with a shield during a clearing operation.

Field testing has not yet begun.

It’s currently being tested in a lab setting with an M4 carbine. But they’re looking to make it compatible with heavier weapons, including the M249 automatic of the M240B machine gun.

“With this configuration right now, we can go up to 20 pounds and take all of that weight off of the arms,” said Dan Baechle, another Army mechanical engineer at work on the project. “Imagine shoulder-firing either of these without the weight on your arms, and without all the recoil going into your shoulder…The research and development we’re focused on now is refining this device.”