High-speed measurement of firearm primer blast waves

TL;DR

This study introduces a high-speed measurement method for firearm primer blast waves, revealing significant variability in peak pressures, especially in lead-free primers, affecting ignition reliability.

Contribution

The paper presents a novel high-speed measurement technique for primer blast waves and provides comparative data on lead and lead-free primers' pressure variability.

Findings

Lead styphnate primers have 5.2-11.3% pressure variation.

DDNP primers show 8.2-25.0% pressure variation.

High variability in DDNP primers causes ignition delays and failures.

Abstract

This article describes a method and results for direct high-speed measurements of firearm primer blast waves employing a high-speed pressure transducer located at the muzzle to record the blast pressure wave produced by primer ignition. Key findings are: 1) Most of the lead styphnate based primer models tested show 5.2-11.3% standard deviation in the magnitudes of their peak pressure. 2) In contrast, lead-free diazodinitrophenol (DDNP) based primers had standard deviations of the peak blast pressure of 8.2-25.0%. 3) Combined with smaller blast waves, these large variations in peak blast pressure of DDNP-based primers led to delayed ignition and failure to fire in brief field tests.