Engineers Patent Limited-Range Projectile To Reduce Collateral Damage


Imagine a bullet that could self-destruct if it missed its target. Apparently, it is not as far-fetched an idea as we might think. Three employees of the U.S. Army Armament Research, Development and Engineering Center (ARDEC) were recently awarded with a US 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 7th May 2013 and were notified of its approval on 1st September 2015.

According to reports by, the official homepage for the US military, 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 is .50 calibre ammunition. However, the patent covers the idea and technology behind the concept as a whole, so it could theoretically be used in various calibres of small arms munitions.

“We wanted to protect the US government’s interests and position,” McFarlane said about filing the patent.


Trial and Error

Computerised modelling and simulation were performed to compare the inventive projectiles to the .50 calibre M33 projectile and the .50 calibre M8 projectile.

“Conceptual designs were run through and evaluated via modelling 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 calibre, 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 of this is that the round does not continue to travel, therefore reducing collateral damage. This benefit can best be described as “a design programmed maximum range” according to McFarlane.

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 calibre from 5.56mm to 155mm.


How the Disassembling Projectile Works

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.

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