Calculating stopping percentage with multiple shots... - Page 2

Tangle · July 8th, 2006, 12:53 PM

In all fairness guys, I don't think krept's intent was to establish stopping power based on mathematically manipulating one shot percentages. Nor does it appear to me that he was suggesting a way to deal with a threat. From the context of his post, he was simply pointing out a potential trap when considering percentages - the point being you can't just add the one shot stop percentages to get a total effect of multiple shots.

AutoFan · July 9th, 2006, 12:05 AM

Not to mention that multiple gunshot wounds cannot be considered equivalent events in the classical sense of statistics, since the initial conditions change after each shot (i.e. your target is already bleeding, lowering the starting blood volume, adrenaline is raising heart rate and blood pressure, your previous shot has already damaged some bodily structures, etc.), so the single shot numbers cannot be manipulated to generate valid multiple shot numbers. But I do understand krept's point about how you would manipulate them if it were valid.

krept · July 9th, 2006, 05:03 PM

:) thanks for the great points to all of you. I am definitely in agreement.

The original post was more to be taken into the context of exactly how Tangle so eloquently explained it above. Sometimes I get so caught up on adding caveats that they end up detracting from the focus (like the photo of a sign that says BEWARE THIS SIGN HAS SHARP EDGES!!! by the way, the bridge ahead is out).

The main reason why I became interested in this was because when Marshall and Sanow data are usually discussed, the folks who stoke their carry weapons with FMJs usually take the leap that if the bullet has X% to stop, if you shoot twice hitting COM you get 2*X% to stop, frequently totalling over 100%.

For the life of me, I had the hardest time trying to get a forumla to explain why it was not additive and someone helped me out with it.

Just for the record, shoot till the threat is stopped is what I was taught. M&S, Fackler, etc. just provide a decent basis for discussion IMO.

thanks again folks, this place is great.

randytulsa2 · July 9th, 2006, 07:58 PM

Too many variables in any give situation to calculate with any real precision, and placement is by far the most important of those variables.

But some calibers and loads are more effective than others. I don't know how to measure that effectiveness, nor can I prove the truth of the statement.

QKShooter · July 9th, 2006, 09:48 PM

Chuck Taylor's formula for the stopping power of a bullet.

WAVY over 1000
W=Bullet weight in grains
A=Bullet cross section in square inches
V=Bullet velocity in FPS
Y=If V=1088FPS or more then bullet expands and 1.25 is the value. If bullet doesnt expand then 1.00 is the value.
The product is divided by 1000

Real Good Chuck. Not one of your shining moments.

July 9th, 2006, 09:48 PM	#15
QKShooter Assistant Administrator Join Date: Dec 2004 Location: Off Of The X Posts: 23,499	Chuck Taylor & His Old WAVY Formula Chuck Taylor's formula for the stopping power of a bullet. WAVY over 1000 W=Bullet weight in grains A=Bullet cross section in square inches V=Bullet velocity in FPS Y=If V=1088FPS or more then bullet expands and 1.25 is the value. If bullet doesnt expand then 1.00 is the value. The product is divided by 1000 Real Good Chuck. Not one of your shining moments.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

July 8th, 2006, 12:53 PM	#11
Tangle Senior Moderator Join Date: Dec 2004 Location: Chattanooga Posts: 6,611	In all fairness guys, I don't think krept's intent was to establish stopping power based on mathematically manipulating one shot percentages. Nor does it appear to me that he was suggesting a way to deal with a threat. From the context of his post, he was simply pointing out a potential trap when considering percentages - the point being you can't just add the one shot stop percentages to get a total effect of multiple shots.

July 9th, 2006, 12:05 AM	#12
AutoFan Senior Member Join Date: Mar 2005 Location: The Sunshine State Posts: 1,143	Not to mention that multiple gunshot wounds cannot be considered equivalent events in the classical sense of statistics, since the initial conditions change after each shot (i.e. your target is already bleeding, lowering the starting blood volume, adrenaline is raising heart rate and blood pressure, your previous shot has already damaged some bodily structures, etc.), so the single shot numbers cannot be manipulated to generate valid multiple shot numbers. But I do understand krept's point about how you would manipulate them if it were valid.

July 9th, 2006, 05:03 PM	#13
krept Member Join Date: Jul 2006 Location: Phoenix AZ Posts: 17	:) thanks for the great points to all of you. I am definitely in agreement. The original post was more to be taken into the context of exactly how Tangle so eloquently explained it above. Sometimes I get so caught up on adding caveats that they end up detracting from the focus (like the photo of a sign that says BEWARE THIS SIGN HAS SHARP EDGES!!! by the way, the bridge ahead is out). The main reason why I became interested in this was because when Marshall and Sanow data are usually discussed, the folks who stoke their carry weapons with FMJs usually take the leap that if the bullet has X% to stop, if you shoot twice hitting COM you get 2*X% to stop, frequently totalling over 100%. For the life of me, I had the hardest time trying to get a forumla to explain why it was not additive and someone helped me out with it. Just for the record, shoot till the threat is stopped is what I was taught. M&S, Fackler, etc. just provide a decent basis for discussion IMO. thanks again folks, this place is great.

July 9th, 2006, 07:58 PM	#14
randytulsa2 Distinguished Member Join Date: Jun 2006 Location: Oklahoma Posts: 1,529	Too many variables in any give situation to calculate with any real precision, and placement is by far the most important of those variables. But some calibers and loads are more effective than others. I don't know how to measure that effectiveness, nor can I prove the truth of the statement.