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.

[Tijeras_Slim]

Now you've done it.

[chance33_98]

Ping for information (I just use hair spray with a lighter myself)

[mict42]

Speed,weight and location.

[Bogey78O]

In terms of physics the round that is able to transfer most of it's power is the round with the most stopping power.

That's why the .45 is so popular. It's large cross section does that quite nicely. But some people like the 9mm because if you use the right type it'll open up nicely and perform very similar.

[sasquatch]

If I remember my physics correctly, force=mass times the square of acceleration.

F=ma; KE=(mv^2)/2

[Fzob]

I'm not an expert in this subject, but I believe location, location, location of the slugs impact is a good barometer of stopping power.

[Woodman]

Foot Pounds of Energy, Expansion of the bullet and accuracy (target placement). In other words Physics and Training (maybe Talent).

[AnAmericanMother]

Well, FWIW, practical experience suggests that the .45 ACP does the job.

I would just get that and fuggedaboudit. :-D

[TERMINATTOR]

Velocity and penetration are important. If the bullet gets stopped by clothing, body armor, etc., there's virtually no stopping power.

[Lonesome in Massachussets]

The only thing that counts in "stopping power" is transfer of momentum. The round has to have momentum = mass x velocity and it has to impart it to the target. A heavy fast round is generally better. Try a 105 Howitzer, if you can aim it with one hand. For hand guns, I think the M1911 (Army .45) if not the winner, is right up there and more than adequate for most work.

If a round passes through a target is does not impart all its momentum. If the round bounces off the target, counter-intuitively, it gets momentum from the target and actually transfers more momentum. If you had armor which caused bullets to bounce off, they would actually transfer more momentum than rounds that stuck to the armor.

In practice, you should chose a weapon for self defense that you are comfortable with. If the recoil or weight of a 0.45 is more than you can comfortably handle, you may be better off with a smaller weapon. Regardless, remember, keep shooting. "Why'd you shoot him 44 times?" , "Ran out of ammunition." One shot from a 0.38 is about as likely to infuriate as drive off an assailant. And shoot to kill. The sternum is a good target, even if you miss you might hit something.

[heckler]

The key is to transmit as much energy as possible from the bullet to the target. In theory you could push a .22 fast enough to carry more enery than a .380. But the cross section of the bullet is so small that it cant transmit its energy to the target rapidly and "shock" the target.

Velocity + mass + a good quality hollow point bullet that will expand rapidly and retain its mass are the key to "stopping power".

[x1stcav]

My formula is,

.45ACP (any quality pistol) + 100 rounds a week (practice) + 2 rounds into the target (tap-tap) = unbelievable stopping power.

[ReaganCowboy]

For what it's worth, the United States Army continues to discover that the 9mm round is inadequate in re 'stopping power' in combat. Multiple complaints coming out of operations in Afghanistan and Iraq are documented in official 'lessons learned' reports.

The reason the Army adopted the .45 in the first place was that the .38 caliber pistol was too weak when used against the Moro tribesmen in the Phillipines, and hence when the .45 was successful in shooting and stopping doped-up insurgents, it became the M1911 service pistol.

I own a Beretta 9mm, and hope to buy a Kahr 9mm for concealed carry, regardless of these facts. Why? Combat engagement ranges are usually in excess of 50 meters, and personal protection situations usually are less than 10 meters. I'm gaining concealment of a smaller weapon for the trade off in stopping power (particularly at distance). Plus I plan and train to shoot two rounds center mass of target, and then re-evaluate the threat.

So, it really comes down to what you're comfortable carrying, shooting and hitting your target with.

[spodefly]

The physics are pretty straightforward regarding the terminal ballistics of various rounds. Obviously, the larger, and heavier, and faster a bullet is, the more energy it has available at impact.

How this energy translates to 'stopping power' is less clear cut. No two people are built the same, and there are examples where a .22 into the arm can 'stop' some people, while 4 or 5 rounds to the chest from a .45 might not be enough to 'stop' someone else (at least in time for it to matter.)

Use as big and as fast a round as you are comfortable using. A fast 9mm round may carry as much energy as a slower but heavier .45 round, but unless you hit something, it won't matter.

Personally, I like the 9mm CorBon +P 115gr JHP. Either that or a firm tone of voice will stop most people.

[Bogey78O]

Have you tried the Taurus PT145? It's a medium sized .45 that holds 10 rounds. In my hand the barrel only sticks out 1.5 inches past my pointy finger when I extend it.

[rudy45]

115gr JHP

Please forgive my possible ignorance, but I gather that JHP is a brand of ammunition, in which each round has 115 grains (?) of gunpowder? Is 115 grains considered much, or little, or in-between? Thanks.

[Pistolshot]

Interesting subject. The Momentum vs. Kinetic energy theories.
Momentum has an emphasis on mass...a la the .45 at a moderate velocity(830-900 fps). 185-200 gr JHP being the most effective in this range.
Kinetic has the emphasis on higher velocity a la the 9mm. The 115 gr JHP at 1300-1500 fps has been the standard, although the FBI tried to up the weight and get closer to the Momentum side with the 147 gr JHP at a sub-sonic velocity(950 fps).
The 10mm was a total step in combining the two., high velocity(1300 fps) and bullet mass and weight(.40 caliber/200 gr JHP)
Problem with the 10mm was it battered the guns badly. So, the FBI went to the 10mm Lite. A toned down velocity(900 FPS). This left a large amount of the case empty and a possible detonation might occur.
In steps S&W with a modified 10mm cartridge....small primered, 200 gr JHP, moderate velocity, substaintial crosssection(.40 cal) and POOF!! the 40 S&W is born.

Now, having said all that, it comes down to which portion of the stopping power curve you want to be on. Recoil plays a key role in this. You certainly want to have control of the weapon...9mm being fairly easy to handle is still adequate for defense. The 125 gr 357 Magnum is sited as the best for stopping power, but you pay in recoil.

FORGET ABOUT 1-SHOT STOPPING POWER. There is no such thing as it takes a brain or spine shot to effect a complete shutdown of a perp, both iffy under stress. Proper bullet placement and 'hit them til they go down' no matter the caliber should be how you train.

[heckler]

Jacketed Hollow Point.
115 grain is the weight of the bullet.

[Gorzaloon]

comments about .380 (e.g. "great for shooting mice" or "what are you going to do with it, THROW it at your attacker?").

As a person who loads and carries many calibers, I think these statements do not bear out with ER statistics. A .380 Hydrashock, etc. can be a deadly round. I do not weigh 300 pounds. I cannot conceal my .45 Colt Combat Commander MKII in the Summertime. I carry a .380 simply because I cannot conceal the Sig 226, either.

I think comments like that are best reserved to the useless and annoying .25ACP. They neglect that fact that in many places, if used in self-defense, you WILL use it at powder burn range, or you will go down for murder.