Ballistic gelatin is a testing medium scientifically correlated to swine muscle tissue (which in turn is comparable to human muscle tissue), in which the effects of bullet wounds can be simulated. It was developed and improved by Martin Fackler and others in the field of wound ballistics. Ballistic gelatin is a solution of gelatin powder in water. Ballistic gelatin closely simulates the density and viscosity of human and animal muscle tissue, and is used as a standardized medium for testing the terminal performance of firearms ammunition. While ballistic gelatin does not model the tensile strength of muscles or the structures of the body such as skin and bones, it works fairly well as an approximation of tissue and provides similar performance for most ballistics testing, however its usefulness as a model for very low velocity projectiles can be limited. Ballistic gelatin is used rather than actual muscle tissue due to the ability to carefully control the properties of the gelatin, which allows consistent and reliable comparison of terminal ballistics.
Since ballistic gelatin mimics the properties of muscle tissue, as compared to porcine muscle tissues, 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 Hague Convention restricts the use of such ammunition in warfare, it is commonly used by police and civilians in defensive weapons, as well as police sniper 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 vermin, such as prairie dogs, for example, needs to expand very quickly to have an effect before it exits the target, and must perform at higher velocities due to the use of lighter bullets in the cartridges. The same fast-expanding bullet used for prairie dogs would be considered inhumane for use on medium game animals like whitetail deer, where deeper penetration is needed to reach vital organs and assure a quick kill.
In television the MythBusters team sometimes used ballistics gel to aid in busting myths, but not necessarily involving bullets, including the exploding implants myth, the deadly card throw, and the ceiling fan decapitation. They sometimes placed real bones (from humans or pigs) or synthetic bones in the gel to simulate bone breaks as well.
The US television program Forged in Fire is also known to use ballistics gelatin, often creating entire human torsos and heads complete with simulated bones, blood, organs and intestines that are cast inside the gel. Various bladed weapons are then tested on the gel torso in order to simulate and record the destructive effects the weapons would have on a real human body.