A Study of the Engraving of the M855 5.56-mm Projectile
Final rept. Jun-Sep 2006
ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
Pagination or Media Count:
The interaction between a small-caliber projectile and its weapon system cannot be readily measured during the launch event. The forces and resulting deformations on the projectile due to engraving are small and localized compared to the ballistic pressure. Consequently, the interaction is inferred from the condition of the projectile after it has exited the barrel. A direct method of examining the engraving force and the resulting projectile deformation is through the use of rate-controlled push tests. This approach allows for the experimental assessment of the load vs. displacement behavior as the projectile engraves and allows for a before and after measurement of mass and diameter. This report employs both a push test methodology to evaluate low-rate dynamic engraving loads as well as a soft recovery approach to evaluate the effect of engraving on the M855 projectile as a function of propellant charge. The result of this combined approach is the ability to evaluate the projectile response to engraving over a range of loads and loading rates and to quantify the dimensional changes to the projectile. The understanding of the projectile-barrel interaction due to the engraving process allows projectile and weapon designers to tailor their approaches to increase projectile launch survivability and performance.
- Ammunition and Explosives