What are the most important factors in determining "stopping power"? (vanity)

self

[rudy45]

I have been investigating various pistols for self-defense/concealed carry purposes. From time to time I see threads on the merits of one caliber vs. another. For example, I have seen snide (g) comments about .380 (e.g. "great for shooting mice" or "what are you going to do with it, THROW it at your attacker?").

I wonder, however, if OTHER factors besides caliber will affect stopping power. Specifically, am I correct that different types of ammunition, though designed for the same gun, can/will have different speeds? If I remember my physics correctly, force=mass times the square of acceleration. Therefore, is it possible that even with a "smaller" caliber such as .22 or .380, I can compensate by having a higher velocity round? In other words, do different types of ammunition vary that greatly in speed as to affect stopping ability? Thanks.

[Lonesome in Massachussets]

delta_p = Integral [ F(t) dt ] ! integrate over reasonable time boundaries.

delta_p is the change in momentum,
F(t) is force as a function of time
dt is incremental time.

Works every time, else Isaac Newton'll kick your ass. Larger surface area causes an increase in F(t) and increases momentum transfer. If the bullet and the armor are perfectly elastic, in case of normal incidence, the round will recoil with the same velocity (essentially) that it impacted with, and the momentum imparted to the (armored) target will be twice the momentum of the round on impact. If the round sticks to the target, preservation of momemtum requires that all its momentum (on impact) be transfered to the target.

[rockfish59]

Well, I heard the 'Mob' uses .22's to the back of the head.

My personal .357 handload is a 110 grain hollow point with 23 grains of 296 ball powder.
At 1,600 fps it should stop something!

[archy]

There's at least one recorded case of an elephant being killed by a .22 short.

Archy, I think you better back that one up. That's too difficult to believe.

Well, I can expound a bit, at least. It was in the early 1970s, when a circus was performing in Ohio. One of the spectators in the crowd was drunk and with a female companion, whom he decided to impress by shooting an elephant in the behind with his little pocket .22, a double-barrelled derringer, of which a couple of types are possible, but was most likely a rimfire copy of the old Remington over-and-under. Unfortunately, the bull turned and faced the shooter, and the 29-grain short bullet went up the beast's nasal cavity, resulting in a death within around a half minute. There was a clown bank robbery skit with blank gunfire and a backfiring clown getaway car going on at the time, and the rube figured he could get away with the pop of a single shot from his hideout gun; he didn't, and the enraged animal handler and other show workers gave him a pretty thorough beating in the process of taking him into custory and disarming him *for the safety of the crowd,* of course!

If I recall correctly, the show was the old Hoxie Brothers circus, later bought out and folded into the Carson and Barnes operation. I first heard details of the story from Jo Ann Stewart of Bloomington, Indiana, an exotic animal supplier who had supplied Barnum and Bailey show cat act superstar Gunther Gabel-Williams with his parrot and a big cat or two; Williams son worked bull elephants. I ran the story past gunwriter Major George Nonte, and he checked out some of the details and got a couple of the written reports of the matter, which resulted in no criminal prosecution, though a couple of real obvious charges like reckless endangerment come to mind. But the drunk was presented with a bill for his trophy safari, and was in a position to pay it and did so, beating any criminal rap. George passed away in 1978, so it would have been a year or two before that when it took place, possibly three. I'll see if I can track anything more about the circumstances and in which city it happened down, and fill in a few more blanks if I can. But kids, please don't try this at home....

-archy-/-

[Shooter 2.5]

That's one for the books.

I figured that it had to be a tame animal but even though when you think about the amount of bone that the .22 short had to go through...

I'll bet the "big game hunter" was as surprised as any when the poor thing dropped.

Thanks for the story.

[archy]

What are the most important factors in determining "stopping power"?

First most important? Availability. The first rule of surviving a gunfight is to have one with you when it happens. And sometimes, just your having one will keep your problems away, just as having an umbrella seems to make it less likekly that you'll be caught in the rain, or the presence of having a first aid kit seems to lessen the odds of the need for one. Of course if an umberella or first-aid supplies are needed, that need isn't as disasterous if the required equipment is at hand and familiar.

After that comes reliability. Neither power nor accuracy will do you any good if anything prevents your most critical first shot from happening, and a stoppage of followup shots can be just as unfortunate if multiple or particularly enthusiastic opponents are involved, with firearms themselves or without.

Then it's accuracy. You *might* get lucky and scare off an inexperienced or amateur burglar or holdup rookie, but you'll more likely encounter some experienced ex-con who'll figure the only out of the mess he's in will be to kill you. Nothing personal. In that case, you'll have to hit him to stop him, or at least slow him down enough that you can both make your escape. And again, if you're facing multiple assailants, you won't want to be wasting ammunition.

After that you can begin to concern yourself with bullet diameters and mechanical systems of operation. But you can learn the principles with inferior equipment, and improve on your gear once you've at least got a rudimentary grasp of the fundamentals. I'd far rather spend $200 for a fair handgun and $300 for ammunition with which to practice, than $500 for something newer and more state-of-the-art with only a box or two of ammo with which to run through it. Handguns that can use inexpensive surplus ammo are a good dweal in this regard, as are those for which reloaded ammunition can be arranged or obtained.

-archy-/-

[George Smiley]

Hunt down the "rec.guns FAQ".

Search using that exact phrase.

There's an entire section devoted to ammunition and a subsection devoted to self-defense ammunition.

[Trooper512]

Stopping power: once upon a time there was not much question about this. The Army used big (and fast) bullets (45 ACP,, 30-06, 308). The frontier shooters (big N.A. game) used big (slower) bullets -- 45 Colt, 45-70, 30-30. Experience taught them that a big bullet was needed to knock down a big target. When they started messing with full auto rifles, the problem became how to carry around all the ammo they can process. (It took 2 guys to carry a BAR and feed it) So they opted for little cartridges. I do not like the 223, but it is adequate for man killing. The 9 mm is worthless (North Hollywood proved it). Skip the engineering tech notes and get a large caliber (pistol .357 mag, .40, .44 Mag or 45 ACP). If you want to shoot through car doors and windows take a magnum. (Rifles: 30-30, 308 or 30-06; Grizzly 300WM). Bullet -- flat nosed lead (SWC) knocks down, jacketed penetrates, JHP does both. Magnums prefer jacketed or JHP. If you need more firepower than this you have a really special problem and need some special planning.

[BigandBad]

assassinations of unaware, unarmed men and stopping a determined attacker are two very different things. A .45 is nothing much, really, with most loads. The Plus P Mag Safe .45, or a hot reload with the 117gr Aquila 4 segment prefrag, tho, will do a pretty fair job, with no more recoil than normal .45 ammo.

[BigandBad]

When Cirillo's NYPD Stakeout unit confronted 280 Armed robbers, in Harlem, in 1968, over 80% surrendered without a shot. The worse stoned, drunk, 3 time loser punks still gave up, even tho they had guns. More WOULD have surrendered, but Jim and his partners shot them down before they had the chance. So the odds are 10 to 1 that you won't have to actually hit anyone with a bullet, IF you get your gun out and "on" them soon enough, and IF you can project that you WILL empty the mag into them, if you have to do so.

[BigandBad]

baloney. the 380 jhp doesn't have enough velocity to expand in flesh, reliably. i've shot dozens of animals with such loads, and it's a joke. There's no reason to not carry a 15 oz, 6" long Kahr PM9 9mm. it's very pocketable and controlable, and with 90 gr jhp CorBon's, it's got about 400 ft lbs (1400 fps) which is at least twice the power of a pathetic 380. At such speeds, the jhp does expand in flesh. Animal tests prove this.

[BigandBad]

.45's usually don't expand jhp's, due to too low a velocity. The 90 gr CorBo9mm jhp DOES expand, viciously so, In a 4" or longer barrel, it has1500 fps, and 450 ftlbs, yet its recoil is very mild. The .45 ball rd usually won't even stop a housecat with a chest hit. It's just had a lot of bs war stories told about it, that's all.

[Lurker]

If I'm not mistaken, I seem to recall that one of the largest bears ever taken in North America was shot just behind the ear with a single shot .22 caliber rifle by an aged Native American woman.

The bear, a grizzly IIRC, was looking for an easy meal. Instead, the old woman got a very nice rug and plenty of bear meat.

L

[EdReform]

BTTT to find later

[Durus]

First most important? Availability... After that comes reliability... Then it's accuracy... After that you can begin to concern yourself with bullet diameters and mechanical systems of operation. (Archy)

That couldn't have been better said. There is way to much hype concerning ammo/caliber selection and Archy, in his wisdom, has cut to the chase. Anything 9mm or greater is a sufficient round if you have met the criteria above.

[Little Ray]

There is no such thing as "stopping power." Physics dictates that every action has an equal an opposite reaction. If a bullet could knock down a target human, then the firearm that launched it would knock down or injure its user.

The reality is "wound channel size." Basically this how big a hole the projectile makes in the person. Bigger bullets make bigger channels; since bullets keyhole ("tumble") when they enter flesh, bullet length can also affect the wound channel size. Finally, the velocity determines how deep the bullet penetrates (and may otherwise widen the wound channel). These are the basic factors governing the lethality of ammo.
There are other factors such hollow points (expands to a larger diameter), jackets, etc.

In the end though, the real "stopping power" is shot placement. What you really want is a fire arm and ammo you are comfortable shooting, then you want to practice a lot. Tape over the sights, too. According to some folks, you might not be able to use them in a real gunfight.

[nightdriver]

"There's at least one recorded case of an elephant being killed by a .22 short."

I'm sure there is.

We heard last year of a full-grown Alaskan Brown Bear that was killed by one pellet from a .410 shotgun that penetrated its nose, went up his nasal cavity and hit his brain. I'd hate to count on that happening if I was in a similar situation, however.