Ballistic gelatin comparisons: Part I
Is clear, synthetic gelatin an acceptable substitute for FBI-standard, 10% calibrated gelatin?
Until the early 1990s, there was no accepted industry standard for evaluating the terminal ballistic performance of duty handgun ammunition for law enforcement. As a result, agencies that wanted to conduct an objective examination of duty ammunition were forced to develop their own test protocols and standards, or rely on the data provided by manufacturers or other agencies (frequently federal agencies, since they had the budgets to do this kind of testing).
A significant limitation of this approach is that it was impossible to compare data from different sources. Every test differed from the next and introduced variables, assumptions and theories that made direct comparisons of the data fruitless. For example, differences in test mediums (water jugs, clay, gelatin of different concentrations and temperatures), pet ballistic theories (temporary cavities versus permanent cavities, “energy dump” versus penetration), and desired performance (penetration depth, expansion, retained weight, cavity measurements) made each set of data individually unique and incomparable.
To illustrate, it’s useful to consider the critical variable of penetration depth, which was measured and rewarded in very different ways in major studies from the 1970s through the early 1990s. In National Institute of Justice testing, bullets were evaluated and scored on their ability to penetrate between 1.6 and 8.7 inches in the test media (20% gelatin), while US Secret Service testing focused on the 1–5.9 inch range (20% gelatin), US Navy testing focused on the 7–12 inch range (20% gelatin), and US Immigration and Naturalization Service testing favored performance in the 9–12 inch range (10% gelatin). Based on this factor alone, it’s easy to see how a bullet that scored highly in one test could fail the test conducted by another agency.
Settling on a standard
When the Federal Bureau of Investigation (FBI) introduced its own standards for terminal ballistic performance in December 1988, they were met with a mix of enthusiasm and resistance. In fairness, there were things to both like and dislike about the FBI standards in their first iteration, but over the course of time, “the protocol” – and, more importantly, the interpretation of the data derived from the protocol – has improved and matured to the point that it’s now the uncontested industry standard.
The protocol has been widely accepted by both the law enforcement and manufacturing communities and has given them a standard to work from. The FBI protocol has established a common language, a standardized testing process and standardized benchmarks for performance that have allowed a variety of different agencies, companies and individuals to conduct their own testing and contribute data that is directly comparable to the data derived from other tests and sources.
This has been a positive influence on the development of duty ammunition. The improvements in communication and information sharing have led to the development of several new generations of duty ammunition that were designed to excel in the stages of the FBI protocol.
The first generation of FBI protocol-inspired bullets – represented by designs such as the Federal HST, Hornady XTP, Remington Golden Saber, Speer Gold Dot and Winchester SXT – dramatically improved the capabilities of law enforcement ammunition. However, a desire for “barrier-blind” bullets that offered more consistent performance after encountering the intermediate barriers of the FBI protocol has led to an even more advanced second generation of bullets, typified by designs such as the Hornady Critical Duty Flexlock bullet, Speer G2 Gold Dot bullet and Winchester Ranger One bullet. Absent the FBI protocol, and its influence on bullet development, it’s doubtful that law enforcement officers would have access to such innovative and capable duty ammunition today.
In an interesting twist though, the law enforcement community is currently in danger of repeating some of the mistakes of the period that predated the adoption of the FBI protocol. Specifically, they are in jeopardy of returning to the time when data sets were not comparable, due to the choice of different test mediums.
Before the FBI standardized the use of (nominal) 10%, calibrated, ballistic gelatin, various groups used materials as disparate as wet newspaper, clay, water jugs, ballistic soap (still popular in Europe), or 20% ballistic gelatin (favored by the US military), shot at a variety of temperatures, to test ammunition performance. Since the widespread adoption of the FBI protocol however, all serious testing done in the United States has been conducted with organic gelatin prepared according to FBI specifications, promoting a high degree of standardization.
Now, with the introduction of a new, clear, synthetic “gelatin” product to the market, this standardization is potentially in jeopardy.
One of the problems with FBI-standard gelatin is that it’s fairly labor-intensive to prepare, store, transport and maintain during testing. The organic gelatin must be carefully prepared to obtain the proper density, stored at low temperature (around 40 degrees F), and shot while the gelatin is still cold. The gelatin must be calibrated by the user (by firing a 0.177” steel BB into the gelatin at a velocity of 590 +/- 15 feet per second, and checking for penetration depth between 2.95 – 3.74 inches) immediately before it is used, and rejected if it fails. The gelatin deteriorates quickly, is temperature sensitive and can be messy to work with.
The hassle of working with properly prepared ballistic gelatin has encouraged the introduction of a clear, synthetic product that’s easier to work with. The new, synthetic product comes prepackaged, requires no “assembly,” has a calibration “guarantee” from the factory, isn’t as sensitive to sunlight, rain, or temperature, and isn’t as messy as calibrated, 10% organic gelatin. It’s also clear, instead of the hazy straw or amber color of 10% organic gelatin, which allows the wound tracks in the synthetic product to be more easily seen and photographed from outside the block. These significant advantages make it a very attractive alternative to FBI-standard gelatin, and many commercial businesses and public safety agencies have begun to substitute it for FBI-standard gelatin in their own testing.
The question that remains is whether the new synthetic product is a viable substitute for the FBI-standard gelatin.
If the clear synthetic product performs identically to 10% calibrated gelatin, then test results derived from the new product can be evaluated using the FBI’s criteria for ammunition performance without issue.
However, if the synthetic product has different qualities than 10% calibrated gelatin, and the ammunition fired into it behaves differently, it’s both inappropriate and misleading to judge the performance of the ammunition using FBI guidelines. In an “apples to oranges” comparison such as this, it’s possible that a law enforcement agency could “fail” a round that would normally pass the FBI’s demanding protocol when it was fired into FBI-standard gelatin, or “pass” a round that would normally fail the FBI’s protocol. In either case, the agency might choose a round that is inappropriate for their mission, and endanger the safety of their personnel and the public.
Warranties, guarantees and questions
The manufacturer of the clear synthetic product guarantees that their product meets FBI specifications, and is therefore a viable substitute for 10% calibrated gelatin.
The manufacturer conducts random testing on every batch of synthetic gelatin they produce. Sample blocks from each production run are tested by shooting a 0.177” steel BB into the gelatin at a velocity of 590 +/- 15 feet per second, as specified by the FBI. If the selected sample block meets penetration specifications, then each block in the batch is considered to have passed calibration. A warranty card is included with each of the untested blocks that lists the penetration of the BB in the tested sample, assuring the end-user that their block from the same batch meets FBI specifications (BB penetration depth between 2.95–3.74 inches).
A sample-based calibration guarantee from the manufacturer is nice, but the FBI protocol requires each individual gelatin block to pass calibration prior to testing. If the actual block is not verified to be within limits, the validity of the data derived from that block would be in question. Therefore, despite the manufacturer’s guarantee, the calibration of the synthetic gelatin blocks must be verified by the user, prior to shooting them.
In early 2018, I was approached by industry professionals with concerns that the clear synthetic gelatin was not passing FBI calibration in their independent testing. Despite the guarantees provided by the manufacturer that their synthetic product performed similarly to 10% calibrated gelatin, it appeared that calibration BBs were penetrating beyond the maximum depth allowed by the FBI. It also appeared that ammunition fired into the synthetic material was performing differently than it normally did in 10% calibrated gelatin, with projectiles under expanding and over penetrating in the new, synthetic product.
As a result of these concerns, I began to collect and compare data on ammunition tests in both mediums.
Unfortunately, there was no entity that had tested both mediums with the same projectiles. Ammunition manufacturers, law enforcement agencies, private citizens and commercial businesses had all tested ammunition in either 10% calibrated gelatin or the clear synthetic gelatin, but none of them had tested the same ammunition in both products.
As a result, I was left to compare data from different sources, with no assurance that the test methods and environmental conditions were consistent between the data sets. Despite this limitation, the publicly available data seemed to indicate a discrepancy between the performance of selected models of handgun ammunition fired into the two test mediums. The reported concerns about performance differences in 10% calibrated gelatin and clear synthetic gelatin seemed to be supported by the available data.
In late 2018, I began to coordinate with a number of ammunition manufacturers to develop a plan for comparing the clear synthetic product and 10% calibrated gelatin in a fair test, to determine if there was a true and meaningful difference between the two products. In order to eliminate variables, the two products would be tested at the same facility, in the same environmental conditions, using the same protocols, weapon and box of ammunition.
The manufacturer of the clear synthetic product was also consulted and brought into the planning effort. With their support and the support of several ammunition companies, I began to prepare for the comparison test.
Coordination continued throughout the early part of 2019, and by early August, the test had been completed.
The data derived from this test is important. For the first time, the two products have been tested by a single source, under identical conditions, using identical methods. This comparison will allow industry and law enforcement to determine whether the clear synthetic gelatin is an acceptable substitute for FBI-specified, calibrated gelatin.
The details of how the test was conducted will be discussed in the next article.