Wounding capacity assessment of small calibre systems in ballistic soap

Authors:

  • Sofia Hedenstierna
  • Patrik Appelgren
  • Melker Skoglund

Publish date: 2011-02-09

Report number: FOI-R--3154--SE

Pages: 36

Written in: Swedish

Keywords:

  • ballistic soap
  • wound ballistics
  • small calibre ammunition
  • injury potential assessment

Abstract

Assessments of the injury potential of a projectile can be performed in order to characterize small calibre weapon systems. This is of interest both to evaluate weapon systems and to analyse threats. To simulate soft tissue targets a surrogate medium is used, like e.g. ballistic soap or gelatine. The cavity that is created as the projectile penetrates the soap is correlated to the energy deposition taking place from the projectile to the target and thereby a measure of the wounding capacity of the small calibre system. To develop and recapture knowledge about the methodologies for wound cavity assessment experiments with ballistic soap were performed by FOI during 2010. The aim was to improve the ability to measure and evaluate the wounding capability for different small arms systems. The results showed a large variability in wounding capability for one small arms system and consequently this must be considered in any evaluation methodology. The most important factor for cavity size for the tested projectiles was the neck length (depth of tumbling), which varied within each shooting range. The variation in cavity size due to shooting range was small for the tested distances and there is need for additional impact velocities in a complete characterization. Depending on the length of the block of soap the amount of information obtained differed. Within the short 14 cm soap blocks the maximum cavity diameter was not reached whereas all projectiles were stopped completely within the 54 cm long blocks, preventing any measurement of residual velocity. Large sources of error in the analysis were the estimation of cavity diameter and the assumption that the cavity is symmetrical. This can easily be improved by measuring in more than one plane. Wound cavity analysis using ballistic soap can be used to evaluate a relative wounding capability of a small arms system compared to other systems. However, to make a proper evaluation of the wounding capability that can be used in developments of tactics as well as protective equipment, it is of great importance to have a thorough understanding of the limitations of this methodology.