I firmly believe that we will never completely settle the ongoing debate about ammo, its performance and what it needs to do.
To be fair, the FBI says that what matters most is one thing: penetration. FBI guidelines were established after extensive testing and after reviewing of the results of previous shootings. The guidelines suggest that 14 to 16 inches of penetration is optimal. In rating ammunition, anything that penetrates ballistic gelatin less than 12 inches is “penalized heavily,” and more than 18 inches of penetration is likewise downgraded, though not as heavily as the under-performing ammunition.
The FBI is also a big believer that pistol calibers very rarely provide an immediate, mechanical stop to human aggression. Most of the time, unless you put a round into the central nervous system, that round is not what stops the bad guy. According to the FBI, the most common reason that people who have been shot stop their hostile activity is psychological. That is to say that most people could keep fighting after taking a bullet, but they choose not to. On the other hand, we have all heard the stories of people continuing to fight despite taking multiple handgun rounds. This is further proof that the bullets are not doing the stopping and gives lots of support to the idea that we must keep shooting until the threat stops.
The reason I say the debate will never really end is that there are people and companies out there that continue to challenge the conventional wisdom and make ammunition that does not fit what the FBI says should work, but that ammo is still doing the job of stopping bad guys.
Two companies come to mind immediately: Allegiance Ammo and Custom Cartridge. Both of these companies are making ammunition that, by most measures, offers devastating results in self-defense shootings. For whatever reason, you do not see this type of ammo much in the media, and you see even less of it in FBI testing. I think the reason you do not see much testing is because of the way these bullets are designed to stop attackers. They hit hard, typically offer less than 12 inches of penetration, and break into thousands of tiny pieces. It is said that the result of this is that the immense hydrostatic shockwave caused by this impact completely disrupts the central nervous system. Take a look at this video. It shows a 9mm round from Allegiance hitting a gel block. Of all the shooting we have done into gel here at Concealed Carry Magazine, we have not seen results like this, so we have ordered some ammo.
You can imagine why there can be some difficulty getting scientific testing done on the effects of this ammo. First up, because the FBI demands at least 12 inches of penetration, not many agencies are using this stuff. With fewer agencies, there are precious few chances to get real-world data. To further complicate things, there is no real testing protocol on what such trauma does to the central nervous system. So, right now, lots of people are talking and wondering.
I have seen some impressive results from this type of ammo against wild hogs, but that information apparently cannot or is not be used in a scientific study of the topic, even though I really wish it could be.
In the end, this frangible, controlled-expansion ammo offers some very impressive performance that the FBI, the accepted authority in the arena, has yet to look into and validate. I wish they would because ammo like this could really be a game-changer in small pistols used for concealed carry.