Study on hangfire failure mechanism in firearm firing-ignition systems.

To investigate the hangfire failure mechanism in firearm firing-ignition systems, gas pressure responses were experimentally analyzed using a firing-ignition simulation test device. Pressure characteristic parameters were statistically evaluated using the "3σ" criterion to establish the hangfire failure thresholds. A finite element model simulating the mechanical-thermal-chemical multi-mechanism coupling process during primer mixture ignition was developed and validated against experimental results. The effects of percussion energy, interlocking gap, charge surface height, and anvil height on primer mixture temperature and gas pressure dynamics were systematically studied. Single-factor and coupled two-factor analyses revealed critical failure boundaries and their influence on ignition performance. Results indicate that reduced percussion energy and charge surface height, combined with increased interlocking gap and anvil height, diminish energy conversion efficiency, delay hotspot formation, and prolong pressure initiation.