FMJ Overpenetration: Truth or Myth?

Dr. Fackler used ballistic gel at a precise ratio and at a precise temperature. He even found a way, using a BB to "calibrate" gelatin. He also used what is called a "Fackler Box" that uses water and freezer bags in a long apparatus that could correlate penetration compared to ballistic gelatin. The Fackler box is a great way for the common man to test bullets for both expansion and penetration. If I remember correctly (possible) it was necessary to multiply the penetration in water by .557 to get the amount of penetration in gel. It is a very accurate way to get repeatable results when testing bullets for terminal ballistics. I built two (the first one blew apart on the first shot) and tested both pistol and rifle bullets. The box is not really very portable and you have to have enough water to fill new bags each time but you get repeatable results every time.
 
I don't know if this has been clearly discussed but examine the standard. 12 to 18 inches in ballistic gel, not tissues. Tissues are different and diverse. Bullets are diverse. Given twenty cartridges that consistently hit an average of 14 inches in ballistic gel, every round shot into an actual body would create random depths of penetration.

It's probable that the fmj rounds will on average, will penetrate further than an expanding round that worked. This is given identical stats of power and bullet weight.

Ballistic gel is simply a way to test performance. Twelve to eighteen is an artificial standard that is believed to be a good enough approximation to human flesh.

Over penetration is probably the most over rated concern. In New York a drug dealer fired a full auto at police who returned fire, and even in New York city there were no casualties from either over penetration or missed shots.

The concern that a round will pass through a body and seriously injure another are really slim, I believe. It's possible that an person might be in exactly the right spot, that the bullet may hit in just the right place, and that the bullet will have enough power left to inflict a serious wound.

It is more probable that the shot will miss, that there will be bystanders. That does not necessarily mean that a miss will somehow magically find its way into a body.
 
With a national police standard of only 20% hit ratio, I'm thinking that over-penetration is not a real factor.
Under different circumstances, civilians hit 80% of shots fired. That has more to do with the adrenaline level than it does training or accuracy. When a guy is breaking into your house, you get to wait until he shows himself. It is a lot different for a cop pulling someone over for a broken light and being ambushed with a gun.
 
I pulled targets next to a Police Chief at the National Matches. He had to account for every bullet fired by one of his employees. He did not like shotguns for that matter, too many pellets!

For me, I want the biggest through hole. I want to encourage drainage. I believe that if it lives and breathes, if you make it bleed enough, it will stop breathing. A big through hole will facilitate the process.
 
Having a front and back hole of probably completely irrelevant. If a person is bleeding internally from a popped vein or just a lot of tissue damage it probably doesn't matter how many holes you put in him. It will seep out into interstitial gaps between the organs, then it will seep through the holes.

If you blow out a major blood supply it may help to have two holes, but if the shot doesn't cause a major bleed it will mostly just accumulate in pockets.

So far, I've never made a game hit that bled outside significantly. Lots of hunters struggle with tracking blood trails because all they did was drip, while the game bled out internally.

I know tha penetration is the current goal, but it doesn't necessarily mean that a through and through shot is the goal. They want it to go deep.
 
Y'all are really giving me a lot to think about. I have guns in 380, 357/38, 9, and 40. The only caliber I've debated over is 380. I carry a 380 more than anything else, and I really don't like the HP results I've seen in gel tests with this caliber. Hornady's CD seems to be the best performer, but even that doesn't impress me much. So I've been debating on using FMJ or maybe Lehigh's Defender just for 380. Hence my interest in the overpenetration issue. I'm satisfied with HST for 9 and 40, and I use Remington's HTP 38+p. I know to some folks the easy answer is to just not carry 380, but I like my Bersa Thunder and G42.
 
.380ACP has trouble making the FBI penetration specs with expanding ammunition. There's just barely enough "oomph" to get deep enough penetration with an expanding projectile in the caliber and many (most?) commercial loads can't manage it.

https://www.luckygunner.com/labs/self-defense-ammo-ballistic-tests/#380ACP
http://shootingthebull.net/blog/final-results-of-the-380-acp-ammo-quest/
http://www.brassfetcher.com/Ballistic Gelatin Tests/380 ACP 10 Percent Ballistic Gelatin.html

Looks like Hornady's 90gr XTP at 800-900fps is a decent performer.
 
Ya the .380 comes up just short in power to make the good stuff happen in the 9mm.

At first I was gonna go with FMJ's but it was just to much penetration imo.. The Hornady loads look about as good as you can hope for I ended up going with the speer gold dots, I'd rather give up a bit of penetration then have to worry about to much..

I don't really expect any 1 shot stops in a handgun, I especially don't think of .380 as a man stopper but anyone hit with one of those gold dots is gonna have a VERY bad day regardless.
 
In my tests, it depends upon the caliber. 45ACP is fat and slow.
Probably not an issue. 9mm will penetrate quite a bit more.

I can't help wondering what situation I would be in, where some
innocent is around, in the background, while I'm being jumped
by a band of thugs. I guess it could happen, I'm just not seeing it.
 
My thoughts? I believe that jello testing is barely relevant. It doesn't match tissues or bullet performance on live critters. it is, however,A good, consistent indicator of what will probably happen in live tissues. fourteen is rather exaggerated. There are few or no encounters that will reach 14 inches, but 14 inches in jello will still represent good performance in tissues. Not performing at peak relative efficiency in jello means very little in the real encounters.

Are you concerned about overexpansion? Probably won't happen. Concerned about under expansion? It will work as well a a fmj, won't it? Concerned about poor penetration? That's a risk that you take. Even an oversized 300 pound lout will take a bullet and it will reach flesh and wound, but the wound will be marginal.

Think carefully. Fat doesn't bleed. Carefully shoot for upper chest, regardless of size, that is where the lungs are, and the least suet.

I carry a .380 too. I use Sig v crown. The seem to be something that will expand only a little, but will expand fully early in penetration.

I believe that you may be overthinking this. Any defensive hp round out today will perform better than fmj. These rounds are much better than earlier designs. They will wound effectively, although it's going to be minimal. A 90 grain bullet at 1k fps or so is not a 125 with higher velocity.

Bottom line? If you want to carry a .380 do so with some confidence. Use combat loads of good reputation,any of them. Using a .380 doesn't mean that you're going to die, it means that you are at a disadvantage compared to guns that are harder to carry.

Again, my reasoned opinion.
 
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Penetration: I'd rather have it and not need it than need it and not have it.

You make the decision to shoot or not and you place your shot to best of your ability, beyond that it's fate.


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If you hit the bad guy in the arm on the way to his heart in a quartering shot how far does a bullet have to travel to make it to the heart?

My tape measure says it will have to penetrate 12 inches with at least one major bone and possibly a rib. Will a bullet from a 9mm do that? Will a 45 ACP do it? I know my 357 will. I figure the bones are about the same size as a mule deer. Shattering the humerus, a rib and hitting the heart from about 45 yards killed that deer.
 
Will a bullet from a 9mm do that? Will a 45 ACP do it? I know my 357 will.
Click to expand...

Given the highly variable results from terminal ballistics, such absolutist proclamations are likely overstated. Assuming that the mule deer analog is a sufficient human simulant, exactly how the bullet encounters bones will have an impact on what the bullet does afterwards. A bone may be shattered by a nick from a bullet that does little to affect its velocity or momentum. Or it may be shattered by a bullet that hits it dead center and doing significant damage to the bullet in the process and disrupting it considerable. The bullet may deflect in an unintended direction. In short, your deer analog shows that there is a potential for .357 to work, not that it necessarily will work as you described.
 
There is no magic bullet. Nothing works 100% of the time. The best things work most often, but even the mightiest can fail, and sometimes sneered at mouse gun calibers result in one shot DRT stops.

The concern about over penetration is justified if you are somewhere that someone else is likely to be at risk. Because, as private citizens we are personally responsible for every bullet we fire, and what it does.

Police agencies are very concerned, because the nature of the work means the percentage of times officers shoot and innocents are at risk is much, much greater than it is for ordinary citizens.

The police, like the military, use weapons and ammo that is decided to be the best overall for the mission. This is not necessarily the same as the best for personal protection & survival.

Personally, I'm in the camp of "better to have it and not need it than need it and not have it". I'm also living in the middle of nowhere, and my nearest neighbor is several hundred yards away and significantly different in elevation, so my concerns are much different from someone living in tract housing, or an apartment complex.
 
I'll second the Mas Ayoob recommendation...many videos of him discussing the salient facts of carrying concealed...he has a reputation spanning several decades of training experience and day to day duty as an LEO. Over penetration is a topic he covers well...in short, you "own" each and every bullet fired in a confrontation...if you hit a civilian, LEO, or other bystander, you can expect to be sued at a minimum or indicted if warranted. Use proper ammunition. Rod
 
There are two sides to this "over-penetration" idea. One side says that a bullet that goes through a perp can injure a person standing behind them or if a bullet goes through it wastes energy. The other cites historical accounts where it is so rare as to be negligible. they also say that if a bullet or cartridge is so anemic that it won't go through in the front on shot it will not be effective in a quartering or side shot.
Lets face facts here; you need a cartridge that you can shoot and that has the power to deliver a lethal shot regardless of the angle. Given that, you have a cartridge that under some circumstances is going to "over-penetrate".

In my mind it is far more important to shoot accurately than it is to shoot a cartridge that doesn't penetrate or "over-penetrate". It is easier to hit a by-stander with a miss on the bad guy than it is to hit a bystander with a round that goes through him. If you see someone behind the bad guy you should be behind cover so you can wait for a good shot.

I carry a 357 Magnum. It is likely to put two holes in the bad guy if I have to shoot. I have been trained to see the background and choose my shot accordingly. I can get low and shoot high to avoid a person behind the perp. It is unlikely that someone robbing me will choose to do so in a crowd. It's going to happen when there are few witnesses. The odds of hitting a bystander after hitting the bad guy are out near the orbit of Nibiru. (astronomical)

Can it happen? YES, Has it happened? Yes. Does it happen often? NO.
You own every bullet that leaves your gun. You have to make the choice yourself, for yourself. I chose a caliber that will penetrate to the vitals from any angle so I have to be aware of what is beyond my target - just like when I am hunting. The only difference is that the deer isn't usually a threat to my life. Still, there might be a hunter in the bushes behind him...
Yep the odds are about the same.
 
Paul Heller's YouTube videos are interesting because all of ammo tests are done with meat targets he builds using pork ribs, leather jackets/pig ears, etc. Most of his ammo tests involve popular or hyped SD ammo but sometimes he tosses in some fmj just to compare. What I've seen in those videos it seems there typically isnt much energy left with fmjs to really chew someone else up. I didn't pay those parts too much mind since I generally pack jhp and missing or clipping a likely moving target is probably the biggest deal in these situations
 
I think you mean Paul Harrell, and ya I like this videos too he's really down to earth.
His meat targets are interesting although I wouldn't use them alone I like gel tests..

However I looked at gel test when I was selecting a .380 load and it did not look good.
Then I came across a video of his and well I won't spoil it.

https://www.youtube.com/watch?v=nX3gpJ-GAy0
 
comparison

There is a very interesting lecture on Youtube as given by an ER staffer to EMS personnel, who seems familiar with both firearms and gunshot wounds. He had a number of X-rays to support the lecture,and makes a compelling case for penetration, though that is not the purpose of his presentation. I do not know how to post a link, but the title of the lecture was :

"Handgun and rifle caliber comparison from a medical point of view"

Regards the Ayoob article, when NYC went to the 9mm, one of the statistics that also rose was the total number of shots fired by officers w/ autos, as to those fired back in the revolver days. The increase in rounds fired was notable. I do not have the numbers in front of me, but it makes sense that if the number of rounds fired goes up, so do all the other bad statistics too, like pass throughs and misses. Thusly, so too the friendly fire and bystander hit count.
 
You are correct and I think it was mirrored thru out the country as LE transitioned from revolvers shot counts per shooting went up.

Im not sure if that indicates more available rounds = more shots taken.
or perhaps it was ineffective ammo choices?

But you're right shots went up, accuracy fell.. although again was the accuracy drop because of a more spray'pray philosophy? or something else?

IIRC the chart I seen showed when the police was using revolvers hit rates was around 50% but after the transition they started dropping and I think they finally settled around 28%. (Don't quote me im working from memory)

I was once told by a retired NYPD officer that his department started weeding out recruits (In the late 90's I think) that showed to much interest in guns.

The philosophy was they didn't want trigger happy cops, An officers greatest weapon was their verbal skills to handle suspects and escalate situations rather than shooting.
They didn't want any Dirty Harry's.

It stands to reason officers who have little or no interest in guns are not going to practice as much and probably not particularly good shots.

I don't really see how any one could deny over penetration is a problem.
Look just cause most missed shots don't hit someone the potential is there.. the fact they don't is probably more based in luck.. Im fairly certain none of us would sit still if someone was firing off guns in their neighborhood.

We know sometimes stray bullets hit targets because we occasionally see on the news how a stray bullet went thru someones wall and killed a kid, often in bed.

If a bullet can penetrate a human body and keep going it may have less energy but how is it any different?

Yes JHP's can over penetrate.. either they don't expand and act like a FMJ or they do and still have enough power to go thru the target completely. But it's better than FMJ which unless you're shooting steel.. really does not deform much even when hitting things like sold wood.
 
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