Engineers patent limited-range projectile to reduce collateral damage

By Eric Kowal, Picatinny Arsenal Public AffairsFebruary 18, 2016

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PICATINNY ARSENAL, N.J. -- Three employees of the U.S. Army Armament Research, Development and Engineering Center, or ARDEC, were awarded with a U.S. patent for their proof of concept work on a limited range projectile.

Brian Kim, Mark Minisi, and Stephen McFarlane filed collectively for the patent on May 7, 2013 and were notified of its approval on Sept. 1, 2015.

The concept for the limited range projectile includes pyrotechnic and reactive material. The pyrotechnic material is ignited at projectile launch. The pyrotechnic material ignites the reactive material, and if the projectile reaches a maximum desired range prior to impact with a target, the ignited reactive material transforms the projectile into an aerodynamically unstable object.

The practical use that the three men intended to apply the concept to .50 caliber ammunition. However, the patent covers the idea and technology behind the concept as a whole so it could theoretically be used in various calibers of small arms munitions.

"We wanted to protect the U.S. government's interests and position," McFarlane said about filing the patent.


Computerized modeling and simulation were performed to compare the inventive projectiles to the .50 caliber M33 projectile and the .50 caliber M8 projectile.

"Conceptual designs were ran through and evaluated via modeling and simulation," Kim said. "Three concepts were submitted with the patent, however, not all were feasible," he said.

"A proof of concept test was perfected and results indicated the need for concept refinement and pyrotechnic mix improvement," Kim said.

The group states that there are significant benefits to the warfighter in using a limited range projectile.

"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."

McFarlane said that the distance in which the round disassembles can be adjusted based on the choice of reactive material used. The benefit to this is that the round does not continue to travel, therefore reducing collateral damage.

This benefit can best described as "a design programmed maximum range," McFarlane said.

The ballistics also match and or exceed the standard round out to the max effective range of the round. In theory, the projectile may be any caliber from 5.56 mm to 155 mm.


The concepts vary, however in theory the process would work like this:

During launching of the projectile, pyrotechnic initiating material is ignited by energy produced by propellant in the cartridge case. Or, pyrotechnic initiating material may be ignited by energy produced by bagged propellant, if the projectile is a separately loaded projectile.

Pyrotechnic initiating material ignites the reactive material. Prior to impact of the projectile or with a target, and while the projectile is airborne, energy produced by the ignited reactive material transforms the projectile into an aerodynamically unstable object. The transformation into an aerodynamically unstable object renders the projectile incapable of continued flight.

In one concept, the projectile is rendered unstable by the melting of the copper jacket, which produces a highly irregular shape. In another, the projectile is rendered unstable by the separation of the cylindrical portion from the base portion and the separation of penetrator from the projectile assembly.


Currently, funding for the project has ceased. However, engineers hope that their concept will resurface as the constant need to provide greater technology for the warfighter increases.

Despite the lack of funding, McFarlane said, "This was the first patent we applied for that has been approved. That in itself is an accomplishment."


Per Army Regulation 27-60 which deals with "Intellectual Property," Government civilian employees and military personnel may be considered for an initial award of $200."

They may be considered for a final award of $500 if certain conditions apply outlined in the regulation.

In this instance, since there were more than one applicant, "When two or more eligible persons are co-inventors, each will receive an initial award of $200. The final award to each eligible co-inventor will be $250."

The concept for the limited range projectile came to fruition when the small caliber ammo development team was funded to investigate the feasibility of a pyrotechnically actuated disassembling limited range .50 caliber bullet.

"It was essentially my idea to create a self-destructing small caliber round akin to the larger caliber ones," Minisi said. "The type of reactive materials to use and how to test it was Steve's idea.

"Brian was instrumental with executing the effort, particularly the modeling and simulation to confirm the concept," he said.


The U.S. Army Armament Research, Development and Engineering Center is part of the U.S. Army Research, Development and Engineering Command, which has the mission to ensure decisive overmatch for unified land operations to empower the Army, the joint warfighter and our nation. RDECOM is a major subordinate command of the U.S. Army Materiel Command.

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