atlctyslkr

June 26, 2006, 05:49 PM

In an attempt to NOT HIJACK this thread, I would like to introduce a little math to the subject.

http://www.thefiringline.com/forums/showthread.php?t=214278

As Posted by me on THR

http://www.thehighroad.org/showthread.php?t=207268

It has been posted and reposted on here the one shot stopping statistics of various ammunition types. What about the two shot stopping statistics? Is double tapping statistically worth it?

Get ready for some math because I have developed a spreadhsheet that answers the question.

I've read many reports that a JHP 38 Special +p has between a 60-70 percent one shot stopping probability.

For the sake of argument let's say you are carrying a round that you know has a 65% one shot stop. (This is a given, you must accept it for the model to work). What would be the probablility that two shots would stop the attacker?

Answer: It's the probablility that one out of two plus the probability of two out of two shots are stoppers. -- 87.75% (Or 1-minus the probability of neither-- which is easier to solve for)

Now you can say "Well I can see one out of two but two out of two, if the first one worked then why do I need a second?" The shots are independant events and you don't know that one or both will work and if so in what order if applicable. Think of it as a coin that has a probability of landing on heads of 65%. You flip it twice what is the chance you will get heads?

What can we use this info for? Well, there have been some threads on how to handle mutiple threats. Simple question: You have two attackers, do you fire at both once each or hit one twice and then move to the other? I guess that depends on the statistics of the round you have. If you're packing a scandium snub 357 you might be better off hitting one each, but if you're carrying a .32 maybe doubling isn't such a bad idea.

http://www.thefiringline.com/forums/showthread.php?t=214278

As Posted by me on THR

http://www.thehighroad.org/showthread.php?t=207268

It has been posted and reposted on here the one shot stopping statistics of various ammunition types. What about the two shot stopping statistics? Is double tapping statistically worth it?

Get ready for some math because I have developed a spreadhsheet that answers the question.

I've read many reports that a JHP 38 Special +p has between a 60-70 percent one shot stopping probability.

For the sake of argument let's say you are carrying a round that you know has a 65% one shot stop. (This is a given, you must accept it for the model to work). What would be the probablility that two shots would stop the attacker?

Answer: It's the probablility that one out of two plus the probability of two out of two shots are stoppers. -- 87.75% (Or 1-minus the probability of neither-- which is easier to solve for)

Now you can say "Well I can see one out of two but two out of two, if the first one worked then why do I need a second?" The shots are independant events and you don't know that one or both will work and if so in what order if applicable. Think of it as a coin that has a probability of landing on heads of 65%. You flip it twice what is the chance you will get heads?

What can we use this info for? Well, there have been some threads on how to handle mutiple threats. Simple question: You have two attackers, do you fire at both once each or hit one twice and then move to the other? I guess that depends on the statistics of the round you have. If you're packing a scandium snub 357 you might be better off hitting one each, but if you're carrying a .32 maybe doubling isn't such a bad idea.