Cartridge testing usually consists of measuring the velocity of the projectile, the accuracy and consistency...
The past two months I have been attacked repeatedly by blocks of ballistic gelatin and so far, I have prevailed. My friends find this behavior eccentric. I get huge tubs of ballistic/ordinance gelatin in powdered form from VYSE, and prepare large blocks of material. I shoot these blocks and record the data. If readers walk away from anything valuable in this article, the lesson should be: Try this at home!
Testing bullet performance in gelatin is only one component of cartridge testing, whose ultimate goal is cartridge selection. Most agencies do very little, if any, testing and rely heavily on “standing on the shoulders” method for a decision. This means that they rely on published data for their information. Since a lot of this data may be directly or indirectly sponsored by advertising, agencies should confirm what they are seeing with a little testing of their own.
Cartridge testing usually consists of measuring the velocity of the projectile, the accuracy and consistency downrange, and the measurement of wound cavities created by the bullet. There is a lot of debate about the “real life” application of the results of the testing, but, at the very least, testing allows one to compare the tendency of one cartridge with another.
When I test a particular cartridge, I shoot it at 25 yards from a rest and measure the spread of the bullets on a paper target. Some use a machine rest, which will give consistent results but often takes the characteristics and mechanics of the human structure that guides the equipment out of the equation. There are cartridge/handgun combinations that are consistently better, but generally 4 inches or less in displacement on a target at 25 yards should be considered adequate for law enforcement purposes. The question is, “How many target groups must one fire before one can be satisfied with the accuracy of a cartridge?”
There isn’t a definite answer, but I like to go through a couple boxes of cartridges before I am satisfied. Bear in mind that accuracy is a single gun/cartridge comparison, so the best we can do is predict the trend of a cartridge against the trend of the handgun. For example, I used a Glock 22 to test 40 S&W and .357 SIG cartridges (using a Lone Wolf Distributors barrel). It is safe to say that my results would be similar to most other users using a Glock 22, simply because of consistency in manufacture. This, by the way, is a very good reason to own a Glock. I measure the velocity of a bullet, using an Oehler Model 35 Proof Chronograph. This model is perfect for testing because one simply has to set the chronograph up and fire through the screens. The product does all of the tabulating and calculations for the user automatically. I get a printout which includes individual velocity, average velocity and standard deviation. This is beyond my math capabilities and I appreciate Oehler Research Inc. for this.
The FBI Test Protocol for law enforcement cartridges actually includes nine different terminal performance events: bare gelatin, clothing, steel, wallboard, plywood and automobile glass. The clothing and glass tests, originally conducted at 10 feet, are duplicated at 20 feet.
The FBI Protocol, and any other bullet testing, is subject to considerable debate. Ideally, the bullet that performs under the broad spectrum of media in terminal ballistic tests is the best choice for law enforcement use, correct? Maybe. Some argue with catchphrases like “stopping power”, “temporary cavity” and “one shot stops.” Others suggest that FBI testing protocol does not really square up with reality. Some offer “more scientific” tests, which include using by-products from butcher shops and similar testing media. The most interesting arguments are the anecdotal ones. They come from examples of single shooting incidents that support (or purport) the efficacy of a particular cartridge.
I have some anecdotes of my own. I was once dispatched to take a statement from a shooting victim who was struck by a single bullet. It was a 25-caliber bullet shot from a 1 1/2-inch barrel handgun. The bullet was lodged 6 1/2 inches into the victim’s left shoulder. That’s correct—the bullet initially struck his bone. The bullet hole aligned with the door column of a 70’s model passenger car made of heavy gauge steel. The bullet would have had to pierce two layers of mld steel en route to the intended target, which I inspected. The victim lived. Is that anecdotal, or what?
At best, my bullet testing is anecdotal. I cannot possibly test enough material to make anything conclusive. However, we all can. That is, if we all share what we have found after shooting ballistic gelatin and any other material with a particular cartridge, it can identify a trend.
The FBI Protocol should be taken seriously. It is not marred by advertising dollars and is done in a scientific manner. The results are easily communicated and are repeatable. If done correctly, variables like ambient temperature and other factors are carefully factored.
I abbreviate my testing to the bare gelatin and automobile glass test. I purchase real auto glass and prop sheets of it in front of the prepared 10-percent gelatin. I can usually get several shots through a sheet of glass and about three shots into a gelatin block. I am looking for expansion and penetration. If I am testing a single cartridge, I shoot heavy layers of clothing, too. I would personally like to do much more testing, but my refrigerator only holds three blocks at any given time.
Here’s what you want your cartridge to do: It should penetrate ballistic material from 12 to 18 inches and expand between 1.5 to 1.75 times its initial diameter, retaining its full weight at its final resting point. It should be able to penetrate intermediate barriers like auto glass and still be “effective.” Handgun cartridges should be able to print about 4 inches or less at 25 yards, which is most often better than the average shooter can shoot.
Since my accuracy testing relies on my own eyes, which are subject to all kinds of factors, this portion is pass/fail. For example, several of the groups I shot with Winchester’s .357 SIG were single holes at 25 yards, with a flyer that opened up the group. When I was putting it down on paper, it was 3.75 inches, but some groups could have been less than one inch without the flyer.
There are a lot of mitigating factors. For example, a hollow point bullet can be impacted by layers of clothing in front of the intended target and the bullet will behave exactly like a solid bullet, meaning it will not “dump” its energy within the 12- to 18-inch area and likely over penetrate.
The logic for the testing protocol is on track. From most angles, the farthest a bullet would have to penetrate is about a foot or so in the human body in order to damage a vital area. Over-penetration means that a bullet has left its intended target, and possibly placed an unintended target in jeopardy.
Other mitigating factors come into play. A bullet which performs well in bare gelatin, opening in the media and increasing its diameter as the hollow point effect occurs, often allows the jacket and lead core separate in after barrier tests. Some companies have compensated for this activity by modifying their design, usually by bonding the lead with the core so it stays intact after the initial shock. Others have gone with using a single metal, usually copper, for the bullet, reducing the opportunity for separation. Still others have embraced the idea of separation by offering products that break into sections on impact.
Separation, by the way, is usually undesirable in tests because one of the measurements is the percentage of the weight of the retained bullet. Most bonding processes are proprietary, including companies that epoxy the lead core with the copper jacket. There is a good reason why I like Remington cartridges: They use brass jackets that are pre-scored for performance and bonded cores. It was hard to prove my justification here. Several of the fired bullets didn’t stay in the block, veering off their original axis. This is reasonable performance, just hard to record. The 45 ACP versions consistently retained 100 percent bullet weight.
The bottom line: Some cartridges do well in accuracy tests. Others do well in bare gelatin tests. Some do well after barrier, but do not expand in gelatin, often causing over penetration. Some shed their jackets when they are not supposed to, others leave trails of fragments in the ordinance gelatin.
The products from reputable law enforcement suppliers like Remington, Hornady and Winchester, by the way, generally perform as advertised. Few of them, however, perform well in every media.
Agencies looking at cartridges really need to take a look at their general needs, too. For example, a rural agency may have tertiary duties, like dispatching large animals involved in motor vehicle accidents. The .357 SIG won’t give an advantage here, but some rural agencies like a cartridge that gives extra penetration on rural pests. An urban agency will likely put more weight in after barrier performance where vehicles are likely cover. Beach patrol? Well, you know.
Here are some of the things I found. (By the way, I predicted these results, but let the tests do the talking.) I have some “real world” experience with the Winchester 40 S&W cartridges. My SGT did a lot of research on its performance before it went on duty, for which I am thankful. The improved cartridge is tested here. This is what I carry now, and this is why. However, if I go with the 45, the Hornady’s Critical Defense is definitely up for critical defense. The Winchester T Series gave a little too much penetration.
I like the .357 SIG because there is inherent reliability in the design. When I was getting ready for this article, I began shooting some Load-X Ammunition Company 115-grain .357 SIG cartridges across my chronograph. I didn’t test the Load-X cartridges, but I have tested them in a previous article. If anyone was wondering why I didn’t test EVERY cartridge out there, there simply isn’t enough time. COR@BON is in my off duty/backup article, which will follow in the near future. I’ll give everyone a hint: As a rule, if it says DPX, it will generally perform in after-barrier tests.
OK, back to shooting Load-X: The 115-grain .357 SIG bullets screamed over my chronograph screens at an average of 1,700 fps. I had to stop and shoot something different just to confirm there wasn’t a variable I was overlooking. I shot dozens of bullets over the screen at 1,700 fps.
Velocity is a component of cartridge efficiency, which opens up another debate. That is, a bullet pushed at a higher speed is usually more efficient. A heavier bullet pushed at that speed is even more efficient. Some like lighter, faster bullets and insist that this is the way to go. Others like bullets which create large holes, pushed to moderate velocities. There are arguments that suggest that the temporary cavity is inconsequential. This may be correct, to a point. For example, if the temporary cavity is captured (like in the cranial cavity), temporary is the same as permanent. If given the choice, I would pick moderately lighter, much faster bullets for a given cartridge.
The problem with .357 SIG lies in the bullet, not the cartridge. They either break up after barrier, or over-penetrate. In previous tests the Load-X bullets tended to shed its jacket. My theory is this: Cartridge makers tend to use bullets designed for the 9mm loaded in the .357 SIG, which do not perform the same way with about 500 fps more speed. This was evident when I shot the Hornady Critical Defense .357 SIG. It gave satisfactory performance, but the jacket and core separated after tempered glass. Still, this cartridge can outrun any 9mm out there, with similar recoil and a reduced low light flash. The Winchester .357 SIG? You bet.
I have added a table of preliminary results. Bear in mind, that these results should be integrated in the overall results of many tests, in order to establish trends. I encourage agencies and individual officers to run their own tests. Most importantly, I encourage officers to adhere to the three rules in cartridge performance:
Shot placement, shot placement, shot placement.
Lindsey Bertomen is a retired police officer who teaches at Hartnell College in Salinas, Calif. He welcomes comments at firstname.lastname@example.org.