What has two thumbs and is a nerd...THIS GUY! (One-Shot-Stop Calculation)

Most of the data may be considered common sense but for new guys like me, it might help make decisions.

After reading so many conflicting threads and opinions regarding one-shot-stop and "big and slow vs. small and fast," I decided to do some mathmatical analysis. I plugged the FBI one-shot-stop data table into a spreadsheet and performed a regression analysis to determine the key factors in ammunition and one-shot-stop %.

The end result was that energy is the largest factor(pretty duh, I know) and bullet diameter is pretty much just as important (less than 1% difference in importance). When the energy is the same, the wieght is more important (twice as important actually) than velocity. Long story short, when in doubt go bigger diameter and heavier.

The following is the equation to determine the estimated one-shot-stop % of a handgun round:

Stop%=(-61.82)+(17.519*x1)+(286.119*x2)+(-.068*x3)+(.022*x4)

x1 = hollow point (0=no, 1=yes)
x2 = bullet diamter
x3 = bullet weight
x4 = bullet velocity

Example: 45ACP 200gr JHP @ 975fps

%=(-61.82)+(17.519*1)+(286.119*.452)+(-.068*200)+(.022*975)

%=92.874

Now everyone grab a cup of coffee and wake up.

OK, now throw a .357 mag - 125 JHP @ 1400 ft/sec into your equation. You get something considerably lower than the .45 ACP, but that round has probably accounted for more one-shot stops than the .45 in police service.

Interesting and fun intellectual exercise (and I'm a numbers guy myself, with a 4th-order polynomial describing my gas mileage), but probably not real useful.

To round out your background knowledge, you might research the Thompson-LaGarde study from 1904, the Hatcher "Relative Stopping Power Index", and the more contemporary Marshal & Sanow work on handgun stopping power, plus the Fackler rebuttal in the Int'l Wound Ballistics Assoc files.

Can you refer me to the FBI data you found?

Perhaps it wasn't FBI, it may have been one of the others you mentioned. There was a link to it in a thread on here somewhere, not sure where. The numbers work out pretty close on most of them except the .357mag and the .40S&W not quite sure why though.

I ran them with my 147gr 9mm, and it came out to 75 and change...Less than I would of thought. But that's why anything worth shooting once is worth shooting twice, right?

Guys like you remind me why I was stone-drunk the day I took my high school chemistry final exam--the only chemistry exam I passed, by the way.

Just shoot 'em with what's in your hand and don't worry about it!

I'm confused. Where is shot placement factored in?

The "big and slow vs. small and fast," is the argument that gave birth to the 10mm, almost as big going almost as fast.

too much math for me. I'll keep my various calibers and carry what fits best for the day and focus on shot placement.

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Originally Posted by rammerjammer

too much math for me. I'll keep my various calibers and carry what fits best for the day and focus on shot placement.

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I agree 100%:aargh4:

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Originally Posted by gasmitty

I'm a numbers guy myself, with a 4th-order polynomial describing my gas mileage),

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I can't afford the 4th order. Three fill ups a month. That's it. :wink:

Bigger and heavier work better than smaller and lighter?

Yes. And....?

I suspected that when most here read "regression analysis" they cover their ears and go "lalalalalalalala..."

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Originally Posted by BlueNinjaGo

I'm confused. Where is shot placement factored in?

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yes I think this is the most important thing that is over looked.

When it comes to binominals, polynominals, and quadratics, Im as dumb as owl $h75. But, this is always a fun topic if you can keep your brain housing group seperate from your emotions and enjoy it. But I agree that you cannot go wrong with heavy for caliber all things being equal. The thing one has to remember is that you can reach a point of diminishing returns if you go to far in either direction.

Did you think of looking at gel tests to see how loads perform in a medium that is similar to human tissue?

That would've saved you some time, since trying to apply equations to something with a ridiculous number of variables is an exercise that doesn't tend to yield any worthwhile data.