Penetration Question

You have to consider ballistic gel used for testing is a consistent medium. That is why it's used for testing. Not water jugs, newsprint, or phonebooks. A body is not consistent. Fat, muscle, and organs are different densities offering different resistance. 12" of fat offers less resistance than 12" of muscle. Throw in a bone and the resistance goes up.

If you have a bullet that goes through that fat and still has enough penetration to get to something vital you'll probably do okay. Make that muscle and you may not get to something vital.

Oversimplified but gives you the idea.

The 12" is a standard set by the fbi and is geared more towards law enforcement who may have to take out a bad guy from say one side or the other, in the Maimi shoot out in the 80's Agent Jerry Dove punched Platt wit a shot thru his arm into his chest. The bullet an early winchester sivertip 9MM just missed reaching his heart. Platt wenton to kill Agents Dove and Grogan and wound four others including Agent Morales who finally put and end to things with six +P 38 rounds out of his model 13 S&W. For civilians where FTF is the most likely sceneraio, the 12" is a bit of an over kill

Sarge7402 said:

The 12" is a standard set by the fbi and is geared more towards law enforcement who may have to take out a bad guy from say one side or the other, in the Maimi shoot out in the 80's Agent Jerry Dove punched Platt wit a shot thru his arm into his chest. The bullet an early winchester sivertip 9MM just missed reaching his heart. Platt wenton to kill Agents Dove and Grogan and wound four others including Agent Morales who finally put and end to things with six +P 38 rounds out of his model 13 S&W. For civilians where FTF is the most likely sceneraio, the 12" is a bit of an over kill

Click to expand...

What makes you think you're most likely going to have a full frontal target?

bullseye308 said:

...it just seems to me that 8-10” of penetration should suffice with not much chance of over penetration in most cases....

Click to expand...

Ammo selection is really up to you. Whatever you choose is the right choice for you, but then people are living creatures and all living creatures react differently to getting shot, so you'll never know until it happens.

Do you have any results or studies of over-penetration hurting bystanders and how common this problem may be?

Just as a for instance, lets say tomorrow at 11:00 AM you were going to be in a shootout, there is no getting out of it. To defend yourself, you could choose any weapon you wanted (whether you currently own it or not), and you didn't have to conceal it, what would you choose?

Would you choose a .380 pistol with 80gr hollow points to insure there is no over penetration, or perhaps you may choose an AR-10 .308 rifle with 165gr bullets and a 20 round mag to make sure you stopped the guy/gal you were going to be shooting it out with, over-penetration be damned?

Barriers, heavy clothing, bone....................... they all disrupt penetration. A standard needed to be set to know what to aim for in regards to performance. I have been concerned about over penetration for years. I worry less about it now. Two holes bleed faster than one. However I do choose my ammo carefully for an urban environment.

460Shooter said:

Barriers, heavy clothing, bone....................... they all disrupt penetration. A standard needed to be set to know what to aim for in regards to performance. I have been concerned about over penetration for years. I worry less about it now. Two holes bleed faster than one. However I do choose my ammo carefully for an urban environment.

Click to expand...

I agree with everything you said except that two holes bleed faster than one. Sure thst’s true, but not significant. In this sense. It is the damage internally that causes the bleeding. The blood doesn’t have to drain out for the victim to die. So a deep penetration will be very damaging because of the amount of tissue disrupted whether the bullet exits or not.

The FBI standard is a minimum of 12" and a maximum of 18" in ballistic gel.

I am puzzled about the concern about overpenetration. Attacks becoming common in America are calling for more powerful and deeper penetrating bullets. Automobiles and trucks are becoming the preferred weapon of choice. Consider the recent incident of the woman that tried to run over the kids on the field at a Little League baseball game.

Also many adults in America are overweight. (Don't believe me. Go check out the customers at your Walmart.) So 12" in a 12 pack belly may not reach anything vital especially if it hits at a angle.

BSA1 said:

The FBI standard is a minimum of 12" and a maximum of 18" in ballistic gel.

Click to expand...

Another consideration is this is a requirement for law enforcement agencies and not specifically a design requirement for civilian use. Law enforcement personnel are very likely to be involved in shootings in crowded areas. Conversely, the civilian concealed carrier, simply by the nature of typical crime is probably more likely to be involved in a shooting event in a less crowded area.

Post 2 answered it. The standard is for ballistic gel, not for living uprights. There is a serious shortage these days of living uprights available for testing in a controlled environment, so the fallback is ballistic gel.

Barriers notwithstanding, just bad guys in regular clothes, it just seems to me that 8-10” of penetration should suffice with not much chance of over penetration in most cases.

Click to expand...

I agree here. Many loads carried by armed civilians would fail the 12-18-inch test in gel, but have stopped many a bad guy.

GRIZ22 said:

You have to consider ballistic gel used for testing is a consistent medium. That is why it's used for testing. Not water jugs, newsprint, or phonebooks. A body is not consistent. Fat, muscle, and organs are different densities offering different resistance. 12" of fat offers less resistance than 12" of muscle. Throw in a bone and the resistance goes up.

If you have a bullet that goes through that fat and still has enough penetration to get to something vital you'll probably do okay. Make that muscle and you may not get to something vital.

Oversimplified but gives you the idea.

Click to expand...

You really nailed this with the first post. Ballistic gelatin provides a consistent medium that can be used for repeatable tests. It might mimic the human body, but it certainly does not equal the human body.

Sarge7402 said:

The 12" is a standard set by the fbi and is geared more towards law enforcement who may have to take out a bad guy from say one side or the other, in the Maimi shoot out in the 80's Agent Jerry Dove punched Platt wit a shot thru his arm into his chest. The bullet an early winchester sivertip 9MM just missed reaching his heart. Platt wenton to kill Agents Dove and Grogan and wound four others including Agent Morales who finally put and end to things with six +P 38 rounds out of his model 13 S&W. For civilians where FTF is the most likely sceneraio, the 12" is a bit of an over kill

Click to expand...

This.
The Miami shootout is what started the 12" requirement in gel.

Ballistics gelatin is a standard of measure. There are a million and one factors that go into how a bullet will perform when hitting a living/breathing target. Was a bone in the way? Was the muscle tissue flexed as the bullet passed through? Heavy clothing? Drugs in the body? The 12-18" was come up with as a standard to compare bullets to each other using a consistent medium. No bones, drugs, muscle or anything like that.

Look at another standard. You buy a printer for home. And want to know how fast it will print. You will find a "pages per minute" measure. Those measurements are usually done with lightweight copy paper. A printer that does 30 PPM will be faster than 10 PPM printer. But if you are using photo grade paper and printing high quality pictures, you may get different numbers. Same thing with bullets.

Sarge7402 said:

The 12" is a standard set by the fbi and is geared more towards law enforcement who may have to take out a bad guy from say one side or the other, in the Maimi shoot out in the 80's Agent Jerry Dove punched Platt wit a shot thru his arm into his chest. The bullet an early winchester sivertip 9MM just missed reaching his heart. Platt wenton to kill Agents Dove and Grogan and wound four others including Agent Morales who finally put and end to things with six +P 38 rounds out of his model 13 S&W. For civilians where FTF is the most likely sceneraio, the 12" is a bit of an over kill

Click to expand...

This is it. The standard is totally semi-arbitrary and based almost exclusively on that one event. Of all the possible conclusions from analysis of the event, the FBI's conclusion was that there was an ammunition failure. They created an arbitrary standard by crafting calibrated ballistic gel and setting a specification for penetration they believed would prevent insufficient penetration. The gel standard specifications are based on Michael Platt's body, but they are convenient, repeatable, and offer consistency in media as a fair basis of comparison in expansion and penetration.

Importantly, ammunition makers followed it. Gunzine writers, blog writers, and reviewers doing their own testing and evaluation (most notably in the last couple years the frequently cited Luckygunner tests) follow it. It has been widely followed since 1989.

The FBI dismissed concerns about overpenetration, publishing that since the overwhelming majority of shots fired by law enforcement do not hit the target, it was unreasonable to be more concerned with overpenetration of the ones that do hit the target. For reference, in the '86 Miami shootout, over 145 rounds were fired in less than 5 minutes. But we should be worried about overpenetration?

As a police officer, I had occasion to shoot a large raccoon during an animal control call. The raccoon was about 12 feet up in a tree, and the shot was quartering into the right ham toward the left shoulder. The ammunition was .40 cal Federal HST 165 gr.; premium ammo, right? The raccoon fell, quite dead. The expended bullet plopped out of the raccoon, into the dirt next to him, expanded pretty as a picture. If I was shooting an armed aggressive attacker, I would need more penetration than that. Over the 40+ years of carrying and shooting handguns for my personal, and professional defense, I feel that the quest for limiting penetration with handgun ammo, is very misguided. The over riding reason our department chose that ammo, was that the officer's vest would stop it, should a bad guy get his or her gun. But that's a discussion for another day...

Ballistic gelatin is not intended to replicate human tissue. No single medium can since human tissue varies so much. There is skin (supposedly equivalent to 2" or 3" inches of gel), fat, muscle, organs (lungs are different from solid organs) and bone. What gel does provide is a consistent testing medium. Differences in expansion and depth of penetration are due to differences between cartridges. When they are between examples of the same brand and model, they describe consistency of manufacture. When they are between different brands/models, they describe differences in design. It's something of a leap of faith to say 12" penetration in gel is enough to reach vital organs while anything beyond 18" is more than enough.

Something else to remember is that the volume of the wound track isn't as simple as the depth of penetration multiplied by the area of the expanded bullet. Expansion takes place over the distance of penetration and is more like a cone than a cylinder. A bullet that quickly expands to its maximum diameter will create a bigger wound than a bullet that expands to the same diameter but only at the end of its travel.

Whenever this comes up, I point out that not everyone--me included--sees this as the absolute the FBI does.
1: the FBI needs rounds that will put someone down, immediately. I'm a lot less likely to meet anyone as determined as they are.
2: the FBI has to take into account cover and penetration through vehicles. If that becomes the situation in my case, that means that A) they are leaving or B) I have to be more worried about not being in the way. Expansion after barrier penetration only factors into my decision if the round already functions as well as another otherwise.
3: those numbers are in gelatin. A human body ranges between that consistency, bone, and open space. Any given round is just as likely to expand less as it is to expand as neatly as gelatin will get it to.

That said, i will not fault anyone for carrying something that conforms to FBI standards.
In my case, though, I also won't fault anyone for carrying something that expands well but penetrates slightly less. I consider about 8" or 9" in gelatin to be getting into the 'about right' range, as long as it expands well within that distance and it can be put in the areas it needs to go.
I consider wound volume important. IMO something that expands to .8" in 9" of gelatin is likely to work just as well on your standard street goblin as something that expands to .5" in 14".
If a 9" wound doesn't hit anything vital in the five-to-sixteen rounds I'd end up sending their way, I guarantee I can outrun them. If that big expansion doesn't happen in the inconsistent mass of a human body, the round's likely to penetrate deeper. Win-win.

If someone doesn't subscribe to my same opinion and wants to limit themselves to the standards the FBI set, that's cool. They're FBI standards for a reason.

I still maintain that outside of actual living humans, live animals are the most objective test medium.

JeffG said:

Over the 40+ years of carrying and shooting handguns for my personal, and professional defense, I feel that the quest for limiting penetration with handgun ammo, is very misguided.

Click to expand...

I agree.

I still maintain that outside of actual living humans, live animals are the most objective test medium.

Click to expand...

The guys (and gals) that are shooting things that can hurt them back, and using guns/rounds that are marginal for the task at hand, are looking for all the penetration they can possibly get.

Kendahl said:

Ballistic gelatin is not intended to replicate human tissue. ...

...Something else to remember is that the volume of the wound track isn't as simple as the depth of penetration multiplied by the area of the expanded bullet. Expansion takes place over the distance of penetration and is more like a cone than a cylinder. A bullet that quickly expands to its maximum diameter will create a bigger wound than a bullet that expands to the same diameter but only at the end of its travel.

Click to expand...

It's correct that gel is not intended to replicate human tissue. Instead, it's a consistent medium with penetration standards "indexed" on human tissue. There was a guesstimate made, which takes a leap of faith as you say to accept, that 12"-18" in specified gel is equal to the range of penetration required to reach vitals in various presentations of human tissue targets. A different media could have been used, like wood. Obviously wood is harder than most human tissues, so the index would be adjusted accordingly. Someone could say, "if it penetrates a 1.5" thick solid oak board, that will assure it will penetrate sufficiently in the intended target." But wood of consistent density is harder to come by, and a medium with a higher density that compresses the penetration index makes it harder to evaluate through comparison. The differences from one round to the next might only be a few millimeters. I can imagine the gel density specified by the FBI rather expands the index a bit, so that it's generally softer than the mean density of the intended target and comparisons are made easier.

With respect to the observation about wound tracks, it is a good explanation of why buckshot is most effective at ranges where it has not spread to a pattern larger than the target and where it will penetrate sufficiently. The entrance wound of a spread load of #4 or 00 buck has a far greater area than a .729 slug. Buckshot has dramatically fallen out of favor because of a misconception that it spreads to a pattern larger than the target and the fractional portion of the load that hits fails to penetrate. So instead, 5.56 carbines that produce comparatively tiny wound channels have prevailed in their stead. Certainly, buckshot loses its effectiveness at some range well before a carbine. I don't know if it's 20 yards or 40 yards.