Over Penetration confusion ...

[axeman_g]

All,
I have been reading the debates over the years ... light and fast vs heavy and slower. .223 vs .308 ... 22-250 versus 7mm or whatever. you all get the picture.

My question is this ... why is the concept of overpenetration a bad thing. I am in now way a psychcist, but this is how it would logically appear to me.

my numbers may be off, I am just using them as an example so dont flame me please.

At 100 yds, you shoot a 170 pd body mass with a 110gr .223 bullet running aprox 4500fps. That bullet nose dives after entry, doing damage and lodging inside the cavity.

At 100 yds, you shoot a 170 pd body mass with a 180 gr .308 bullet running approx 3500 fps. That bullet enters cavity, starts expanding and exits body after cutting a larger damage path.

To me, the large entry wound, expanding damage path and then larger exit would would cause more physical "damage" plus causing more trauma therefore more shock, then one smaller entry wound and a series of small damage paths inside the cavity.

I know this is a never ending debate, but I wanted to throw in here. The concept of having to shoot opposing enemies numerous times with small light bullets bothers me. I personally want heavy and damagins as much as possible.

But, my preference is probably because of my personal inclination to be more defensive minded then offensive minded. Power and cover vs speed and number.

Axe

 

[fix]

At 100 yds, you shoot a 170 pd body mass with a 110gr .223 bullet running aprox 4500fps.

That's a hot load!!!

 

[El Rojo]

I think you are confusing two subjects. In a combat situation, there is no such thing as over penetration. There is only incapacitated and still shooting back. In combat the goal is to permenantly disable the enemy. The least number of shots this takes is better.

In a non-combat situation, you have to worry about over penetration. For self-defense you have to take into consideration what is on the other side of the target. If you only have a split second due to unforseen circumstances, then you can't worry about what is beyond your target. So the idea is to have a defense round that does not tend to shoot through the target and onto what is beyond it. That leads people to try and use a round for self-defense that delievers maximum stopping power and the least chance of moving onto an unintended target. For legal reasons this is imperitive. Yeah you might save your life, but end the life of the child on the other side of the bad guy. Not a good thing both criminally and monetarily.

In hunting the same concept applies for the most part. For varmints, you might be hunting in big open areas. You want to maximize damage and death upon the varmint, but you don't want a big heavy bullet skipping across flat land for a couple miles or even a couple hundred yards. That is why a good hollow point will impact and then break up and not travel out of the animal or not too far past the animal. Now for big game, you want to minimize meat damage while maximizing organ damage. That is why you use bullets that expand in a controlled fashion and they retain their energy deep into the animal. The problem with those bullets on varmints is they go right on through and down range a ways.

What anyone will tell you is that shot placement is pretty much the key. If you can get good hits, you can stop someone. Whatever weapon you decide on, practice with it. I am sure you can die from a .223 bullet just as easy as a .308 bullet if you hit someone in the head or in the heart.

And yes, your numbers are pretty far off. I will give you some better numbers to use as a reference, not as a flame, but just so you know.

55 or 62 gr. .223 at about 3200 FPS (+-100). I believe the largest .223 bullet they make is about 80 grs.

150 gr. .308 running at about 2750 (+-100). A 180 gr. .308 will only go 3500 FPS in a super hot magnum of some sort. A 180 gr. is more likely to be going somewhere between 2600 and 3300 (MAX).

 

[JShirley]

The only thing I would add to that, would be that penetration in a defensive round does need to be deep enough to reach major organs. Some extremely shallow wounds with rounds designed to be low penetrators have not incapacitated the aggressor.

John

 

[Cosmoline]

YOU ARE CORRECT! An exit wound is exactly what you want to kill faster. This business about how a bullet does more damage by stopping mid-way is nonsense. Hunters have long known that it's the big exit wounds that kill game. Humans are no different. Shock is not caused by "energy deposit" or other nonsense, but by massive loss of blood causing a drop in blood pressure and death.


Overpenetration is only a concern if someone is standing behind the bad guy who may not be a valid target. While this is a theoretical concern, IMHO the best way to deal with it is STILL one massive wound to the intended target. Fewer bullets in the air mean fewer bystanders are likely to get hit. LEO's and "self defense experts" will sometimes advise you to stay with a small handgun because of "overpenetration" fears. What they overlook is the fact that even trained LEO's will often miss with half their rounds, and each handgun bullet that misses has done far worse than merely overpentrate. So basically to avoid having parts of a bullet exit the back of the bad guy, these fellows are opting to use an inherently inaccurate platform that only hits perhaps half the time at close quarters in a firefight.

Bottom line--if you have a long gun use it. Handguns are only for self defense if you have nothing else at hand.

 

[artherd]

My question is this ... why is the concept of overpenetration a bad thing. I am in now way a psychcist, but this is how it would logically appear to me.

Please refer to the following website and photographs.

I suspect you may no longer 'think' along the lines of .223 being ineffective.

In reality, the .308 FMJ wastes most of it's power on the dirt behind the guy you wanted to take out. Not nessicarily a bad thing, either round should DROP most people in short order.

.223 on the other hand, delivers all of it's energy onto the target (usually, it too can exit and because of fragmentation, the exit wounds can be ghastly.)

 

[axeman_g]

thanks for the replies

and for checking my numbers .....

I am talking about penetrating through the target being more effetive then staying inside the target. Shock incapacitates faster then internal damage I think.

If I punch a piece of wood with my fist, beside crying hysterically afterwards, and I I only give enough enrgey to get part way through the wood, that will be an ineffective attempt to break the board. If I throw the punch hard enough to pass throughm the wood will be total broken through.

I quess I trust speed and weight and would be more confident with a large caliber MBR.

But I am slow and large myself so maybe I am biased.

Thanks all ....

 

[444]

There has been much written on this subject as you note. I am sure you could spend the better part of an afternoon just reading the opinions on this board alone.
"Shock incapacitates faster then internal damage I think."
Shock is hypoxia at the cellular level. In this case, the hypoxia is caused by two factors: blood loss (which is what carries oxygen to the cells), and reduced function of the lungs caused by direct trauma and air inside the chest cavity. The more blood loss, the more damage to the vital organs, and the more air that enters the chest cavity; the faster the person succumbs to their wounds.
At reasonable ranges (you mention 100 yards), a COM hit with a centerfire rifle is going to cause a massive wound. In my opinion, debating between the two cartridges you mention is guilding the lilly. Another big factor is the type of bullet being used. This gets into another can of worms.
Overpenetration: This is certainly an issue for the private citizen, so the next question is, what circumstance do you see yourself using a centerfire rifle for self defense. If you were thinking of making a centerfire rifle you primary means of self defense, I would place overpenetration up higher on the list of considerations. For example, if I was planning on using a rifle for home defense, I probably wouldn't be using a .308. If you are thinking more along the lines of a TEOTWAWKI, one in a million possibility, I wouldn't be much worried about overpenetration.

 

[Cosmoline]

Note that the cited ballistics diagrams show the impact of a FMJ 7.62 NATO. Nobody who doesn't have to abide by the idiotic Hague convention should use FMJ's for anything but paper. They are essentially bullets 100+ years out of date. The 5.56 FMJ, of course, is notorious for failing on impact. This is no substitute for a proper SP bullet. Trust me, a SP .308 hunting load will rip the heart and lungs out of a black bear or moose. It would certainly do the same to a bad guy. Bad guys with no heart or lungs don't shoot back.