In December, 1988, the FBI Academy Firearms Training Unit (FTU) designed and implemented the FBI Ammunition Tests. The test designs are based on research and consultation with experts in the fields of wound ballistics, forensic pathology, wound research and medical research. The full report of this research is available to Law Enforcement Agencies and Military Units on the FBI Ammunition Data and Sniper Targets CD ROM. This CD may be obtained from the FBI Ballistic Research Facility.

The tissue simulant utilized in FBI ballistic tests is Kind & Knox or Vyse 250-A ordnance gelatin. The mixture is 10%, by weight. The mentioned research shows that properly calibrated 10% ordnance gelatin is a reliable tissue simulant. Validation of ballistic gelatin is verified by firing a .177" steel BB at 590 feet per second (fps), plus or minus 15 fps, into the gelatin, resulting in 8.5 centimeters (cm), plus or minus 1 cm, penetration (2.95"- 3.74"). During FBI tests, any gelatin blocks which fail the validation test are discarded. Validation results are not published due to the Pass/Fail nature of the test.

The gelatin is mixed in the following manner (assuming a 20 pound block is desired):

• Weigh out two (2) lbs. of gelatin powder2 and place aside.
• Weigh out 18 lbs. of hot 60˜C (140˜F) water in a plastic bucket. (Note: The FBI utilizes a scale which weighs to the nearest .01 lb).
• Add 2.5 ml. of Foam Eater to the hot water.
• Add approximately .5 ml. of oil of cinnamon to the hot water (prevents fungus growth).
• While utilizing a battery-operated drill with a mixing paddle attached, mix the water to the point of forming a whirlpool, but without introducing air into the mixture.
• While the water is being mixed, slowly add the gelatin powder.
• Pour the mixture into a clean mold pan.
• Allow to stand at room temperature for approximately 4 hours.
• Write date on small square of cardboard and place on top of mixture.
• Place pan with mixture into refrigerator set at 4°C (39.2°F).
• Allow to cure for 36 hours (note: larger blocks require longer cure time e.g. an 80 lb. block requires 96 hours to cure).

Blocks, over time, deteriorate and are temperature sensitive. Former FBI publications advocated utilizing blocks within 20 minutes of removal from the refrigerator (a general statement pertaining to ambient temperature indoors). Allowable time outside the refrigerator is, however, relative to the temperature of the test environment (e.g. a block removed from a refrigerator and maintained in a room at the same temperature as the refrigerator will retain its validation significantly longer than one placed outside on a hot summer day). Note: some authorities believe mixing procedures may vary the consistency of gelatin. FBI studies indicate, however, that a block which displays the required level of penetration, within the required velocity range, is a "valid" tissue simulant.

The FBI Ballistic Research Facility conducts its tests in an environmentally controlled shooting laboratory. Blocks of gelatin are removed from the refrigerator and checked for validation. Only valid blocks are used for testing. Blocks used in testing of conventional pistol ammunition are approximately 6.25" X 6.25" X 16". The initial block of gelatin used in a test is called the Primary Block. Each Primary Block is utilized for a maximum of 5 shots, one in each corner, approximately 1.75" from the nearest edge, and one in the center. Tests conducted by the FBI indicate this placement of shots results in substantially the same penetration as single shots into virgin blocks of gelatin. Any shots which cross the wound path of previous shots are refired. Primary blocks are not utilized for more than 5 shots, to include any shots which are refired.

Because some shots may penetrate more than one block of gelatin, one or more "stopper" blocks are placed behind the primary block. The stopper blocks may be utilized for more than one test, provided that wound channels are not crossed. At the end of each test, the stopper block is placed back into the refrigerator while another stopper is utilized with an unused Primary block. Stopper blocks may receive more than 5 penetrations, provided that no wound channels are crossed (e.g. a stopper which has 5 penetrations of 3" into one end can be flipped over and again used as a stopper). The FBI does not reuse gelatin. Used blocks are discarded.