The US Army Research Laboratory has teamed with other Department of Defense agencies in a high priority project to improve tracer round technology so that only US soldiers, and not their enemies, can exclusively visualise the travel path of shots fired

Tracer rounds today are used primarily with fully automatic firearms; they give off a “large flame behind them during flight allowing observers, including the target, to see where the tracer was fired from. With non-combustible tracers, only the rear of the bullet is emitting light directly at the shooter, which greatly reduces the ability of others to determine the shooter’s location. This increases survivability of our forces,” explained Daniel De Bonis, a materials engineer in ARL’s Weapons and Materials Research Directorate.

He said creating a non-combustible, low observable tracer (LOT) round solution would eliminate the pyrotechnic material that gives traditional combustible rounds their ‘fireworks-like effect.’

“The manufacturing process is simplified as no separate manufacturing wing is needed in the ammunition plant. Traditionally, a separate wing is needed to handle the pyrotechnic material in the combustible tracer. This improves manufacturability.

“Conventional combustible tracers lose mass during flight, which changes the weight of the bullet during flight. This creates a trajectory mismatch with the bullets it is supposed to represent. Since (these rounds) normally are linked one to every four conventional rounds. That means the majority of bullets are possibly not hitting the target the tracers are. It is planned to incorporate every round with non-combustible tracer technology, thus assuring (soldiers) are hitting what (they) see. This increases lethality,” De Bonis said.

ARL designed testing methods unique to this application that simulated the short light bursts similar to gunfire in which the materials were simultaneously heated. “This had to be done in complete darkness to prevent the materials from being charged up by ambient light. We have been able to evaluate a very large number of materials specifically for this application,” he said.

“ARL has been instrumental in developing a field test to determine the propellant wavelengths during propellant burn inside of the barrel,” said Matt Horch, small calibre production engineer at the US Army Armament Research, Development and Engineering Center (ARDEC). ARDEC is the lead systems integrator in this effort and responsible for the final design and manufacturability of the low observable tracer effort. “Dan and his team have provided great support and key testing modifications to help ensure we get the data we need. This test is a joint Integrated Product Team effort but the data recording setup is ARL’s design.”

The low observable tracer round uses materials which produce light energy from the firing process. These materials are similar in concept to the commercial phosphorescent, or glow in the dark materials found on watches and emergency signs, said De Bonis.

But commercial phosphorescent materials do not work well under the high temperature. He said: “Heat can affect the physical structure and energy pathways in certain phosphorescent materials. When these materials are heated, their ability to store and release light energy can change. Some materials lose the ability to store light when heated. Others just emit light out of the material faster. ARL and its partners are looking into producing materials which work best for this application.”

ARL’s military coating technologies expertise aided efforts to identify coating materials that could be applied to phosphorescent materials on the backs of bullets. “Coatings need to be chemically stable with the materials being used, tolerate extreme environments, not reduce the performance of the trace signature nor the ballistic performance of the round itself,” De Bonis added.

The effort is being sponsored by the Army’s Program Manager, Maneuver Ammunition Systems at Picatinny Arsenal, New Jersey, and a team formed of ARDEC at Picatinny Arsenal, New Jersey, the Army Research Lab, in Aberdeen, Maryland, the US Army Corp of Engineers based at Fort Belvoir, Virginia, who specialise in phosphor material chemistry, and the Naval Research Laboratory, Advanced Laser Concepts Group in Washington, D.C. are jointly advancing low observable tracer technology to provide increased capability to our warfighter.