Three workers at the U.S. Army Armament Research, Development and Engineering Center have been awarded a patent for a proof-of-concept “Limited Range Projectile” that disassembles itself if it travels too far, thus reducing the chances of collateral damage.
Several different concepts were developed for the bullet, though as the Army explained that each version follows a similar basis. When the projectile is launched a pyrotechnic material is lit. The pyrotechnic material then ignites a reactive material which burns until the round travels a predetermined distance. Once the desired range is reached, the lit material turns the bullet into “an aerodynamically unstable object,” stripping it of the ability to continue traveling.
In one variant, the bullet’s instability begins when its copper jacket burns to the point that’s its shape has been dramatically altered, causing the bullet to drop to the ground. In the other version, the ignition causes the bullet to break at its base, center, and tip.
The type of reactive material chosen determines how long the round travels before it begins to break apart, according to Stephen McFarlane, who developed the patented system along with Brian Kim and Mark Minisi. He said that this ability to adjust the distance traveled before assembly is best described as “a design programmed maximum range.”
Since the team of researchers received funding to create a .50 caliber disassembling limited range bullet, they developed the proof of concept through the use of computerized modeling and simulations based on the .50 caliber M33 and .50 caliber M8 round.
In addition to being made for the .50 caliber, the Army said the system could be used on projectiles ranging from 5.56 mm to 155 mm.
"The biggest advantage is reduced risk of collateral damage,” McFarlane said. "In today's urban environments others could become significantly hurt or killed, especially by a round the size of a .50 caliber, if it goes too far."
Funding for the development of the projectile has ended. Despite the setback, the workers hope that the concept could later be used for another project. If not, McFarlane doesn’t feel that the effort was in vain.
"This was the first patent we applied for that has been approved,” he said. “That in itself is an accomplishment."