Ballistic Gelatin

In response to inquiries, here is the procedure for making and using gelatin test blocks.  This data is the standard procedure developed by the International Wound Ballistics Association.  Properly prepared ballistic gelatin has been shown to give penetration and bullet expansion characteristics within several percent of that in swine tissue.  Testing of various media gave the following penetration data.  Keep in mind that the wide variance of data in swine tissue comes from the non-homogenous nature of live tissue and that 10 percent gelatin falls well within the observed norms.

While I don't have the cite for the expansion replication enough data has been accumulate to safely state that expansion is within ± 3 percent of what is observed in actual wounds.

Please note that gelatin testing cannot be used to predict the "effectiveness" of  ammunition. 

Testing bullets in gelatin as a soft tissue simulant provides useful information about a bullet's terminal mechanical performance and wounding producing effect and nothing more. These two characteristics are directly linked to the bullet’s design, construction, and velocity. 

Terminal mechanical performance is a measure of bullet penetration, expansion, fragmentation and yaw at a given velocity.

Wounding producing effect is the disruption produced by a bullet’s terminal performance characteristics in the target.

To be "effective" a bullet must inflict an injury that produces dysfunction of the central nervous system. This is accomplished by either or both direct physical damage to a central nervous system structure (the bullet must penetrate the brain or cervical spinal cord), or blood loss in quantity to rapidly deprive the brain of the oxygenated blood it needs to remain conscious (the bullet must penetrate a major cardiovascular structure).  The effectiveness of ammunition is thus a consequence of shot-placement (the bullet’s path through the body), its penetration, and the tissue/organs destroyed.  It cannot be measured in a tissue simulant.  However, a bullet/ammunition that displays good wound producing effect in a simulant will most likely perform well in a live encounter, all things being equal.

General Procedures For Preparing Ballistic Gelatin

1. Use Kind & Knox Type 250A Ordnance Gelatin, or Vyse Ballistic Gelatin*

2. Always start with cold water (45-50°F or 7-10°C)

3. Always add the powdered gelatin to the water; never pour water into gelatin.

4. The most convenient way to control the mixture is to weigh the gelatin and measure the water volume. The mixture ratios are given in the following table for various units.

A 10 % solution should produce standard gelatin, but some users find that a slightly higher gelatin percentage is required to meet calibration (usually they get about 9.5 cm penetration of the test BB), even when good procedures are used in preparation. A 1 % increase in gelatin mixture ratio (e.g., 10 % to 11 %) will decrease the penetration by about l cm.  The 11% mixtures are given because some experimenters have found that even with careful and proper preparation that 10% mixtures for unknown reasons sometimes cannot meet the BB calibration test.  Increasing the mixture to 11% cures this problem

4. Agitate (by stirring) a bare minimum just to wet all particles (avoid violent agitation to prevent entrainment of large quantities of air).

5. Let stand in refrigerator for 2 hours to hydrate all gelatin particles.

6. Heat the gelatin in a hot water bath or double cooker, and again stir gently until all gelatin is in solution and evenly dispersed throughout the container. Do not heat over 104°F (40 °C)!  Do not stir rapidly, as this may entrap air.

7. Pour into molds and store in refrigerator at 40°F (4°C). Do not use for 48 hours after pouring into molds.

8. Blocks must be shot within 30 minutes of removal from the refrigerated storage.

Miscellaneous Notes

• You can add 5 ml propionic acid per liter of solution to inhibit mold.

• Blocks can be reused by carefully and slowly heating to the melting temperature and then rechilling per the above procedures if reshot within 48 - 56 hours.

* Vyse Ballistic gelatin is available in 25 pound buckets for small users as well as 50 and 100 pound quantities, from

Vyse
5010 N. Rose St.
Schiller Park, IL 60176
1-800-533-2152
1-847-678-4780
1-847-678-0329 (FAX)
www.vyse.com
Sales & technical help: sales@vyse.com
Information: info@vyse.com

Ask for Gary Brunet and tell him I sent you. 

Gelatin Block Sizing & Use

The following guidelines should be observed

1. Minimum block size for handguns should be no smaller than 4.5" x 4.5" (11 cm x 11 cm) and the length should be approximately the expected penetration.  However shorter blocks can be placed end-to-end in contact to achieve the desired length.
2. The center of the wound track should be at least 1.5" (4 cm) from the edge of the block and multiple shots should be at least 1" (2.5 cm) from any other track.
3. To yield reproducible results the gelatin should be calibrated using a standard BB shot (preferably 2 shots) at 590 ± 15f/s which should give a penetration depth of 3.3 ± .6" (8.5 ± 1.5 cm)  measured from the front surface of the gelatin block to the leading edge of the BB.

While one can go crazy calculating compensation factors for different velocities and penetration for the BB shot the easiest procedure, and the one recommended by Dr. Fackler, is to simply adjust the distance of the muzzle of the BB gun to the gelatin so that the impact velocity is within parameters and to then simply record the penetration distance and present it with your data.

Updated 2006-06-05