In light of the below, do test results through Clear Ballistic Gel have any value? If so, how should we use them?
I've always known that ballistic results from Clear Ballistic Gelatin were only approximations of testing through 10% calibrated organic gelatin. However, I recently discovered that tests through Clear Ballistic Gelatin may not be even close to accurate when compared to test results through organic gel, which is what the FBI uses for their tests. I thought I would pass this along because I do not recall reading about either of these on the gun forums I visit (of course, I could have missed them).
The backstory. I've looked at a large number of ballistic gelatin test results over the years in many different calibers. In some instances, particularly in .380, a round might look good in one test and fail miserably in others; e.g., the Federal 90 gr. Hydra-Shok. So I recently started collecting data from a number of gel test results on .380 to see if there was one bullet that reliably penetrated and expanded through heavy clothing (note: I use FMJ when carrying a .380). Many of the tests were through Clear Ballistic Gelatin with some testers counting maximum penetration before bullet bounce-back, others not doing so, and still others using a formula to adjust for the bounce-back. This led me to search for information about how to account for bounce back.
During my search (to which I have not yet found a conclusive answer), I found two articles anyone interested in terminal ballistic tests should read.
Brass Fetchers. One article is from Brass Fetchers titled "Brass Fetcher Ballistic Testing: Scaling Penetration Depth from Clear Ballistics Gelatin to 10% Ballistic Gelatin."
The testers fired 20 rounds of one 9mm load through Clear Ballistic Gelatin and 20 of the same load through 10% organic gelatin. They found that the rounds penetrated 2.6 inches more in Clear Ballistic Gelatin than in organic gelatin. The rounds through the organic gel expanded 0.005 inches more than in organic gel. They did a similar comparison using a particular 180 gr. .40 S&W load and found the rounds traveled 4.6 inches further in Clear Ballistic Gel than in organic gel. The rounds expanded 0.015 more in the organic gel.
Brass Fetchers noted the Clear Ballistic Gel was less dense than the organic gel and theorized this caused the different results. It then suggested conversion formulas for each of the two calibers tested using JHP loads moving at similar velocities as the tested loads. So, the "fix" they suggest has very limited application. That is not to suggest I am bad-mouthing their work. To the contrary, I find it very enlightening. I just think that the formulas have limited usefulness. BTW, there is no mention of BB testing to see if either gel met FBI calibration standards. And this leads into to the second report.
PoliceOne.com. The second article is actually the third in a series from PoliceOne.com titled "Ballistic gelatin comparisons: Part III" that came out this past January. Up front, the article states that "none of the factory fresh, clear synthetic blocks passed FBI calibration, despite the fact that the included warranty cards indicated they would." The BBs traveled further through Clear Ballistic Gel than organic gel, even after bounce-back. Like the Brass Fetchers article, this article also found the rounds tested penetrated further than they do in organic gel and expanded less. The author stated: "The average expansion for all the bullets we tested in the clear synthetic was only 92.2% of what we saw for those same bullets in the 10% calibrated gelatin...." This was true in bare gel and gel with a heavy clothing layer, but the results were not consistent between different types of rounds tested; e.g., 147 gr. Speer G2 Gold Dots in 9mm and 124 gr Federal HST 9mm.
Of the rounds tested through bare gel, the over-penetration, when stated as a percentage, was fairly standard and averaged traveling 35.5% further in Clear Ballistic Gel. With a heavy clothing barrier, there were greater differences in over-travel depending upon round-type tested:
Of interest, all of the above results were obtained by using "virgin" Clear Ballistic Gelatin. When melted down and re-formed, the recycled gel came closer to meeting FBI calibration standards.
Unlike Brass Fetchers, the author did not think there was a "conversion formula" that could be used. The author also opined that users of Clear Ballistic Gelatin should verify calibration and that the product was unsuitable as a substitute for 10% calibrated organic gel.
The author stated he contacted the manufacturer of Clear Ballistic Gelatin who said they would take a closer look at their product and quality control testing.
I've always known that ballistic results from Clear Ballistic Gelatin were only approximations of testing through 10% calibrated organic gelatin. However, I recently discovered that tests through Clear Ballistic Gelatin may not be even close to accurate when compared to test results through organic gel, which is what the FBI uses for their tests. I thought I would pass this along because I do not recall reading about either of these on the gun forums I visit (of course, I could have missed them).
The backstory. I've looked at a large number of ballistic gelatin test results over the years in many different calibers. In some instances, particularly in .380, a round might look good in one test and fail miserably in others; e.g., the Federal 90 gr. Hydra-Shok. So I recently started collecting data from a number of gel test results on .380 to see if there was one bullet that reliably penetrated and expanded through heavy clothing (note: I use FMJ when carrying a .380). Many of the tests were through Clear Ballistic Gelatin with some testers counting maximum penetration before bullet bounce-back, others not doing so, and still others using a formula to adjust for the bounce-back. This led me to search for information about how to account for bounce back.
During my search (to which I have not yet found a conclusive answer), I found two articles anyone interested in terminal ballistic tests should read.
Brass Fetchers. One article is from Brass Fetchers titled "Brass Fetcher Ballistic Testing: Scaling Penetration Depth from Clear Ballistics Gelatin to 10% Ballistic Gelatin."
The testers fired 20 rounds of one 9mm load through Clear Ballistic Gelatin and 20 of the same load through 10% organic gelatin. They found that the rounds penetrated 2.6 inches more in Clear Ballistic Gelatin than in organic gelatin. The rounds through the organic gel expanded 0.005 inches more than in organic gel. They did a similar comparison using a particular 180 gr. .40 S&W load and found the rounds traveled 4.6 inches further in Clear Ballistic Gel than in organic gel. The rounds expanded 0.015 more in the organic gel.
Brass Fetchers noted the Clear Ballistic Gel was less dense than the organic gel and theorized this caused the different results. It then suggested conversion formulas for each of the two calibers tested using JHP loads moving at similar velocities as the tested loads. So, the "fix" they suggest has very limited application. That is not to suggest I am bad-mouthing their work. To the contrary, I find it very enlightening. I just think that the formulas have limited usefulness. BTW, there is no mention of BB testing to see if either gel met FBI calibration standards. And this leads into to the second report.
PoliceOne.com. The second article is actually the third in a series from PoliceOne.com titled "Ballistic gelatin comparisons: Part III" that came out this past January. Up front, the article states that "none of the factory fresh, clear synthetic blocks passed FBI calibration, despite the fact that the included warranty cards indicated they would." The BBs traveled further through Clear Ballistic Gel than organic gel, even after bounce-back. Like the Brass Fetchers article, this article also found the rounds tested penetrated further than they do in organic gel and expanded less. The author stated: "The average expansion for all the bullets we tested in the clear synthetic was only 92.2% of what we saw for those same bullets in the 10% calibrated gelatin...." This was true in bare gel and gel with a heavy clothing layer, but the results were not consistent between different types of rounds tested; e.g., 147 gr. Speer G2 Gold Dots in 9mm and 124 gr Federal HST 9mm.
Of the rounds tested through bare gel, the over-penetration, when stated as a percentage, was fairly standard and averaged traveling 35.5% further in Clear Ballistic Gel. With a heavy clothing barrier, there were greater differences in over-travel depending upon round-type tested:
Of interest, all of the above results were obtained by using "virgin" Clear Ballistic Gelatin. When melted down and re-formed, the recycled gel came closer to meeting FBI calibration standards.
Unlike Brass Fetchers, the author did not think there was a "conversion formula" that could be used. The author also opined that users of Clear Ballistic Gelatin should verify calibration and that the product was unsuitable as a substitute for 10% calibrated organic gel.
The author stated he contacted the manufacturer of Clear Ballistic Gelatin who said they would take a closer look at their product and quality control testing.