Army ‘third arm’ device may make shoulder firing large weapons a breeze for future infantrymen

The U.S. Army is continuously looking for ways to lighten the load its soldiers are burdened with in a combat zone.  Sometimes, that means improving the materials used in the equipment our soldiers need while in harm’s way.  Other times, it means experimenting with a shift in the way we carry our gear, trying to develop new ways to carry the same stuff in a more efficient, convenient manner.  Such is the case with the Army’s new “third arm” device intended to replace a soldier’s rifle sling.

While exosuit technology is currently under development, it will be decades before a fieldable version of the tech makes it way to infantry groups in theater, but that hasn’t stopped the Army Research Laboratory from borrowing elements from exosuits in order to make a lightweight addition to the infantry soldier’s loadout that is meant to make carrying a weapon, and firing it with deadly accuracy, easier than ever before.

“We’re looking at a new way for the Soldier to interface with the weapon,” said Zac Wingard, a mechanical engineer for the lab’s Weapons and Materials Research Directorate. “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.”

The goal of the “third arm” is simple: take the weight of the weapon system out of the soldiers arms and distribute it throughout the core of his or her body.  Optimally, it could reduce fatigue and even injury, particularly as new weapon platforms are introduced that could potentially be even heavier than modern rifle platforms.

“You wind up pushing that Soldier’s combat load up beyond 120 pounds and they’re already overburdened,” Wingard said last week at the Association of the United States Army’s Global Force Symposium. “We [now] have Soldiers in their late teens and early 20s and they’re getting broken sometimes in training before they see a day in combat.”

“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, also a mechanical engineer with the program.

A current M16 rifle with a fully loaded thirty-round magazine weighs in at just under eight pounds, which may sound light, but anyone that’s gone on a long patrol can tell you that carrying your rifle at the ready can eventually leave your arms fairly worn out.  A heavier weapon system will only increase that fatigue and leave soldiers more prone to injury.

The device currently weighs in at a mere four pounds, and can support the full weight of a rifle as distributed through the waist to the soldier.  In order to test its use, researchers at Aberdeen Proving Grounds equipped soldiers with the device and an M4 carbine, then placed sensors at strategic places on their bodies to measure muscle activity and fatigue.  They also compared rifle accuracy with and without the device to see if it the reduction in weight management translated to more accurate shooting.

Testing is still underway with the device, and researchers admit that it isn’t currently anywhere near production.  More testing is required in order to ensure the device doesn’t get in the way of the movements required of a soldier under hostile fire, and to find the right way to position it so as not to block a soldier’s access to things like their medical kit or additional magazine pouches.

Despite the long road ahead, Baechle has high hopes of fielding the device in order to allow soldiers to more effectively carry larger platforms, like the M249 squad automatic weapon or M240B machine gun.

“Imagine shoulder-firing either of these without the weight on your arms, and without all the recoil going into your shoulder,” he said.

Baechle also envisions even larger weapon systems seeing use in the arms of soldiers in the near future.

“We could potentially look at very high recoil systems that aren’t going to beat up on the Soldier like they normally would,” he added.

Other potential applications include using the device to carry a shield while breaching, or to hold the rifle in place for quick action while doing something that requires both hands like cutting through fences and the like.  Before any of these applications can be tested, however, the team at Aberdeen are working to “ruggedize” the arm in order to ensure it can survive the rough lifestyle of an American infantryman.

“Right now we’re just doing proof of concept, so we’re not diving into the dirt with our only prototype,” he said. “But that’s something we would want to make sure we can do, because Soldiers will be doing that.”

This third arm may not see use in the field any time soon, but it is yet another on the long list of new developments aimed at making American service members more efficient and deadly in combat.  In the years to come, a serious transition in the methods we employ may take shape, with advanced technologies changing the way we aim, shoot and even carry our firearms while operating in hostile areas.

We may be a long way away from Iron Man, but each step brings us a bit closer to reducing American casualties and maintaining a tactical advantage over our opponents elsewhere in the world, whomever they may be.

Image courtesy of the U.S. Army