Local effects of three standard assault rifle projectiles in live tissue

A total number of 64 anaesthetized Finnish homebred pigs, weighing 25-30 kg, were wounded in the medial part of one thigh. The shooting range was 30 and 100 m. The weapons were the Finnish M 62, the Russian AKM 47 and the American M 16 A 1, and the projectiles were their standard military ammunition. Simulating typical field conditions the skin of the pigs was covered with a Finnish terrain uniform at 30 m. After trauma the anaesthetized pigs were kept under intensive care for 6 hours before they were debrided on current principles of missile injury operation. The condition of the animals was carefully checked both clinically and in laboratory tests. The pigs showed no signs of shock during the study. The impact and exit velocities were measured, and the respective energies were calculated. At the range of 30 and 100 metres the rate of energy transfer was the same, or 8-9% of the impact energy, with the two 7.62 projectiles. The 5.56 American projectile had a considerably greater energy transfer at the range of 30 m (27.5% of EI) as well as at the range of 100 m (14.4 of EI). With all projectiles the same correlation was observed between debrided tissue per unit length of wound path and rate of energy transfer per unit length of wounds caused by the 5.56 calibre projectile were more injurious than those caused by the 7.62 calibre bullets. The wounds and the tissue damage were estimated by gross appearance, amount of debridement, biopsies and ultrasound studies. The results were comparable with those obtained with soap blocks, except as regards the behaviour of the Russian 7.62 calibre projectile, which was quite different in soap blocks compared to live tissue at both ranges.