The use of gelatine in wound ballistics research

Abstract

Blocks of gelatine are used in both lethality and survivability studies for broadly the same reason, i.e. comparison of ammunition effects using a material that it is assumed represents (some part of) the human body. The gelatine is used to visualise the temporary and permanent wound profiles; elements of which are recognised as providing a reasonable approximation to wounding in humans. One set of researchers aim to improve the lethality of the projectile, and the other to understand the effects of the projectile on the body to improve survivability. Research areas that use gelatine blocks are diverse and include ammunition designers, the medical and forensics communities and designers of ballistic protective equipment (including body armour). This paper aims to provide an overarching review of the use of gelatine for wound ballistics studies; it is not intended to provide an extensive review of wound ballistics as that already exists, e.g. Legal Med 23:21-29, 2016. Key messages are that test variables, projectile type (bullet, fragmentation), impact site on the body and intermediate layers (e.g. clothing, personal protective equipment (PPE)) can affect the resulting wound profiles.

Keywords: Bullets; Gelatine; Lethality and survivability; Temporary and permanent cavities.

Fig. 1

Ammunition. a Ammunition components: bullet, propellant and cartridge case which contains the primer in the base (left to right). b 7.62 x 39 mm bullet (fired from an AK47 rifle) cut in half lengthwise, mounted in Bakelite and polished; the core (c) and jacket (j) can be seen. c 5.56 mm NATO bullet (fired from a military rifle) fragments recovered from a block of gelatine; note the tip of bullet (arrowed)

Fig. 2

Typical stills from high-speed video footage illustrating extent of temporary cavitation in a 250 mm × 250 mm × 500 mm 10% (by mass) gelatine blocks conditioned to 4 °C (bullets circled). a 9 mm Luger FMJ [21]—a bullet fired from a pistol that tumbles through gelatine. b 0.223 Remington [6]—a non-military bullet fired from a rifle. This bullet expands, does not tumble and remains in the block. c 7.62 × 39 mm [23]—a military bullet fired from a rifle that tumbles; the bullet captured in a second block

Fig. 3

Typical temporary cavities in 10% (by mass) gelatine blocks and mapped onto the human body. a 9 mm FMJ with reference to [21]. b 0.233 Remington with reference to [6]. c 7.62 × 39 mm mild steel core (MSC) with reference to [19]

Fig. 4

Example of a 5.5 mm diameter steel ball bearing (impact velocity = 654 m/s) penetrating a 250 mm × 250 mm × 500 mm gelatine block (10% by mass, conditioned to 4 °C). Maximum temporary cavity is shown and the final position of the ball bearing is circled.