Measurement of Combustion Products in Small Arms Blowback Gases
ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL NJ PICATINNY ARSENAL United States
Pagination or Media Count:
When a muzzle device, specifically a suppressor, is added to a small arms system, it typically has a tendency to increase the systems backpressure, therefore increasing the blowback. Different muzzle device designs result in different increases in backpressure, and thus different levels of blowback. If the pressure is high enough when the bolt opens, gas will escape from the barrel and into the operating mechanism. In this effort, electrochemical sensors were used to measure and quantify the combustion products of the blowback gases using suppressed and unsuppressed small arms systems by both a Chamber Method as well as a Breathing Zone Method. While the combustion products consist of a variety of gases, the three primary toxic constituents are carbon monoxide, ammonia, and hydrogen cyanide. Results showed increased concentrations of gases with the use of suppressors. In addition to gaseous combustion products, metals are also aerosolized during combustion and firing of a round. Aerosolized metals, including copper, zinc, and bismuth, were measured. Results showed that some aerosolized metals become trapped in the suppressor during firing, resulting in lower levels of the aerosolized metals when a suppressor is used, while others are increased proportionally in the blowback gas when a suppressor is used.
- Ammunition and Explosives