Compare 9mm, 40 S&W and 45 ACP in Self-Defense Shooting?

B

BCGlocker

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First, let me preface that this is not a caliber debate. Rather, it is my curiosity of the difference between three most popular calibers in self-defense.
All the recent ballistic tests showing with the modern bullet designs, the ballistic gelatin tests showing penetrations are relative similar between 9mm, 40 S&W and 45 ACP. Thus, many law-enforcement agencies are embracing the 9mm caliber.

However, as all competition shooters know that when it comes down to knock down power of the pepper poppers, the larger/major caliber rounds will have more power and take down the popper faster. So, 9mm, 40 S&W and 45 ACP all have similar penetration in ballistic gelatin (presumably in body issue), how do we account for the increase knock down power in 40 S&W and 45 ACP in self-defense shooting?
 
There is absolutely difference between the knock down power of 9mm vs. larger calibers on pepper poppers. In competition, 9mm shooters (myself included) will frequently fire several rounds at a poppers in order to get it out of way faster to have access to other targets behind it (i.e. a row of poppers or the fall of the popper that will activate a mover.
 
Let me short circuit this discussion:

.45 shooters: blah blah Browning blah blah perfect gun blah blah. Consensus, just throwing a .45acp round at a car will blow the door clean off. Actually shooting it will explode a Tiger tank. 9mm aren't real bullets and can be stopped by heavy fog and are shot by plastic pea shooters.

.40 shooters: we're awesome because we have more rounds and more power. .45s are fine but too big. 9mms are ok but can't make a fist sized hole in concrete like ours can.

9mm shooters: .45s are for grandpa back when he was fighting the British in the Civil War. 9mms are cheap and we can load it on Monday and shoot it all the way to Sunday. With new ammo we're as good as .45s, right? .40s are good but they carry two rounds less than our Glockenspiel 56 which holds 97 rounds.

.357 revolver: EVERYONE else just inhales - its...a revolver shooter! Uncle Joe was right. They're...real...

10mm shooters: wimps.


EDIT: BCG-want to have fun? Hit a popper with a shotgun round. Squee!!!:D
 
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@BCGlocker,

I think it is fairly simple if you look analyze the physics of it. E=½MV². A ballistics chart I found shows the following:

Caliber Weight (grain) Muzzle Velocity (fps) Muzzle Energy (fp)
9mm 115 1155 341
.40 S&W 180 950 361
.45 ACP 230 850 369

When it comes to shooting poppers, all of the energy is deposited into the target (since it does not penetrate the target). Poppers don't care about expansion or surface area. If you shot the same exact spot on the popper with each caliber, the one with the most energy would knock down the popper more forcefully.

Human targets are obviously much more complex and things like wound channels and sufficient penetration are factors in a bullet's effectiveness.
 
BCGlocker, you cannot logically or honestly claim that your post is not intended to stir the pot, while actively stirring the pot.
 
stephen426 pretty much summed up the hard facts.

Zincwarrior wins Mr. Congeniality for putting a pretty face on the extreme sides of the caliber debate. .
 
Glenn E. Meyer said:
I knocked down a pepper popper with a 32 HR magnum that I was firing outlaw in an IDPA match. HOW did that happen?
Click to expand...

Here some possibilities... ;):p:D

1. Someone else shot your target with a "real bullet" at the same time
2. You have magical powers
3. It was windy and the wind actually knocked it over. Your bullet just helped.
4. LUCK!

LOL
 
Not saying it is impossible 9mm or smaller caliber can knock down popper; I am saying larger caliber knock the popper down with more authority. I carry both 40 and 9, so I am not arguing which caliber one should carry. Just want to know the physics of it.

I think Stephen426's answer is what I am seeking. It seems to me it should be comparable to a punch to the popper. The heavier the punch is to the popper, the faster it will fall. I would think this heavier punch in larger caliber must have some effect on the person being shot.
 
The FBI has a heralded or non-sensical (pending your bias, if any) report that covers handgun calibers in shootings pretty well. Some good info in it.

Sent from my SM-G900V using Tapatalk
 
Pepper poppers have nothing to do with self-defence. They're shooting game targets only. Pepper poppers are 'set' by the match operators to be knocked over by whatever cartridge they feel like. Takes forever for one to go over after being hit with a cast 230 grain .45 from under 10 feet(I think it was). Isn't going to go over any faster if it was hit with a jacketed 230 either.
"Knock down" power of a particular cartridge on bad guys is a myth. No handgun cartridge has any such thing. Physics doesn't allow it. That Newton guy wrote a law about it.
"...many law-enforcement agencies are embracing the 9mm..." Everything government agencies do is about money. And rarely anything else. Police went to 9mm, 30 some years ago, because they could buy pistols that weigh less but have greater magazine capacity at prices the tax payer could afford.
 
I think Stephen426's answer is what I am seeking. It seems to me it should be comparable to a punch to the popper. The heavier the punch is to the popper, the faster it will fall. I would think this heavier punch in larger caliber must have some effect on the person being shot.
Click to expand...
Energy may very well have an effect on a solid structure like bone.

However terminal ballistics have a lot of variables. Where it hits a person, velocity, bullet design and construction, bullet diameter, bullet weight. The latter are just two of the many variables.

Even energy itself is based on weight and velocity, not bullet diameter.

Keep in mind that two of the most historically respected handgun calibers, 45 ACP and 357 Magnum are very different. One is a slow, heavy round and the other is a very fast, light round. Both have a lot of energy.
 
if you miss, it doesn't matter what you are shooting. shoot the caliber that you are most accurate with under time pressure. good self defense loads all have about the same energy. i'll take more rounds on board that i also shoot better.
 
Knocking down steel plates or bowling pins is irrelevant to stopping an aggressor. I can throw a baseball and knock over steel plates and bowling pins.

Stopping an aggressor involves a bullet that penetrates deep enough to reach vital organs. Bullet diameter and weight are largely unimportant and larger calibers can be a handicap. Bullets that are longer in relation to diameter tend to penetrate deeper all other things being equal.
 
Leaving aside real world considerations, and since all three main rounds have approximately the same amount of energy, AND that energy is more than sufficient to the task of knocking over a popper /steel plate, AND that there is NO penetration involved,..

WHY do they seem to fall faster (when it in the right spot) with bigger calibers??

I simply don't know. My GUESS is that it might be due to something I can't quantify that I'll call "dwell time" and involves momentum/inertia, not just pure ft/lbs of energy.

Bullets don't penetrate the steel, nor do they fall to the ground in front of it, so clearly not every bit of their energy is transferred to the popper.

So, I think its a matter of how much (%) is transferred DURING the time the bullet is in contact, "pushing" on the popper.

Might it not be that the larger, heavier, SLOWER moving bullets "push" LONGER even though on paper the energy level is the same???

Think of a safe door. SLAP the door, and it barely moves. PUSH the door, with a force equal to the slap, but over a longer period of time, and the door moves.

Might it be just that simple???
 
Don't forget the discussion that relatively slower wadcutter 38 SPL rounds are more effective than faster hollow points (that don't expand from shorter barrels). The wadcutters cut a cleaner wound channel for more tissue damage.

This is such an old discussion.
 
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