Ballistic gelatin
Ballistic gelatin is a mixture of gelatin dissolved in water. Ballistic gelatin closely simulates the density, viscosity and electrical resistance of human and animal muscle tissue, and is used as a standardized medium for testing the terminal performance of firearms ammunition. Ballistic gelatin is used rather than actual muscle tissue due to the ability to carefully control the properties of the gelatine, which allows consistent and reliable comparison of terminal ballistics.
Preparation
Ballistic gelatine is prepared by dissolving 1 part gelatine in 10 parts of water (by weight). It is then chilled to a temperature of between 5 and 10 degrees Celsius (41 to 50 degrees Fahrenheit) before use. A standard steel BB fired from a BB gun over a chronograph at a velocity of 600 feet per second is used to calibrate the gelatine immediately prior to use. With a velocity variation of no more than 10 feet per second, the BB should penetrate between 3.25 and 3.75 inches into the gelatin. If the penetration is not within the given range, then the gelatin is rejected.
Uses
Since ballistic gelatin mimics the properties of muscle tissue, it is the preferred medium for comparing the terminal performance of different expanding ammunition, such as hollow point and soft point bullets. These bullets use the hydraulic pressure of the tissue or gelatin to expand in diameter, limiting penetration and increasing the tissue damage along their path. While the Hauge Convention restricts the use of expanding ammunition in warfare, it is commonly used by police and civilians in defensive weapons, and by police snipers and hostage rescue teams, where rapid disabling of the target and minimal risk of overpenetration are required to reduce collateral damage.
Bullets intended for hunting are also commonly tested in ballistic gelatin. A bullet intended for use hunting small varmints such as prairie dogs, for example, needs to expand very quickly to have an effect before it exits the target, and must perform at lower velocities due to the long ranges generally involved in the hunting of such game. The same fast expanding bullet used for prarie dogs would be completely unsuitable for use on medium game animals like whitetail deer, where deeper penetration is needed to reach vital organs and assure a quick kill.
Forensic ballistics also uses ballistic gelatin in the recreation of wounds caused by firearms or explosives. Ballistics gelatine was introduced to the general population by the television shows MythBusters and CSI: Crime Scene Investigation, which show ballistic gelatin used in such a capacity.