The OP requested that I chime in on this thread based on a comment I made on another thread. While some of you know me and my credentials, many do not, so I will give a brief background. I am a court endorsed ballistics expert who has worked on multiple firearms failures, shooting reconstructions and I am pretty sure I was the first ballistics expert to combine the use of virtual autopsy with tissue energy thresholds to determine bullet entrance velocity into a human. I have worked as a consultant doing T&E on several cases involving rifle rounds as a threat to personnel and material for LEAs including HSA. Much of the knowledge I have I just simply will not post in an open forum as it is well beyond the need and may be used for nefarious purposes. On some of my cases, while the information is relevant to the OPs topic, the specifics can not be discussed as I have signed a NDA.
While to the lay person, it may seem that there are too many variables, what-ifs, etc., the math, physics and tools available to evaluate the physical aspects of terminal ballistics are very solid, and repeatable. What is not perfectly repeatable, is an individual reaction to an identical wound. While I have participated in live testing of animals related to TCCC and ballistics, the physiological response of animals is NOT the same as with humans. To take the reaction of a deer and equate that with a human is a mis-step scientifically. I have shot several hundred head of big game and often use game animals to test (obviously all within the legal confines of the state in which I am hunting) ballistics theories as well as taking extra time during field dressing to evaluate bullet performance. I have shot deer with 9mm pistols up through the medium and large bore calibers at ranges inside 100 yards.
Based on my observations and work, varmint grade bullets from about 55 grains and down are not what I would put in a SD .223. I will admit that years ago, before a lot of LE and Civilian shooting data with .223 was in existence, I thought a 50 grain Ballistic Tip at about 3000 fps was a good idea, but no more. There are several cases of LE shootings using 55 grain and lighter varmint grade bullets with failures to stop. 60 grain and heavier bullets are what I would look at now. In that realm, there are of course choices.
Light varmint grade bullet failures have been claimed in several cases I have reviewed after someone else did the analysis. I have opined on bullet failures in other cases. In most of those cases, heavy clothing, significant fat, appendages or large bone stopped the bullet. In a few cases, the entrance was on the edge of the torso. In my opinion, with the light varmint grade bullets, they lack the penetration when encountering pretty much anything. In the compilation, the limited set of data I have suggests 55 FMJ ball is a better stopper than varmint grade bullets.
OTOH, the high fragmentation rounds from heavier bullets did not have the same types of failures, and bonded bullets even less. While I agree that the FBI handgun 12" is not a good litmus, I also do not think deer hunting bullets, which we want to mushroom and then exit, are the best answer either.
I can not give you a one-bullet for all answer, and I am not sure that will ever be the case. Another constraint that LE has that a SD does not have is terminal performance at distance. There are some loads being sold to LE that past about 75 to 100 yards have a very high chance of failure due to the bullet design and loss of velocity, others are fine out past 300 yards. Distances and bullet selection are something you will have to evaluate based on your constraints. I do however feel confident in saying that if you use an AR for SD, pick a bullet of at least 60 grains or more.
I have been able to review the ballistic data from several mass shootings as well. Those shot with .223 had the highest death rate. Those shot with buckshot had the highest survival rate. When added together with LE shootings and justified SD shootings, it is clear to me that the .223 is a MUCH better stopper than a handgun which is better than a shotgun with buckshot. 12g slugs and battle (or hunting) rifle calibers are, of course, better than the .223, but they are used so little. I hope this helps some of you.
While to the lay person, it may seem that there are too many variables, what-ifs, etc., the math, physics and tools available to evaluate the physical aspects of terminal ballistics are very solid, and repeatable. What is not perfectly repeatable, is an individual reaction to an identical wound. While I have participated in live testing of animals related to TCCC and ballistics, the physiological response of animals is NOT the same as with humans. To take the reaction of a deer and equate that with a human is a mis-step scientifically. I have shot several hundred head of big game and often use game animals to test (obviously all within the legal confines of the state in which I am hunting) ballistics theories as well as taking extra time during field dressing to evaluate bullet performance. I have shot deer with 9mm pistols up through the medium and large bore calibers at ranges inside 100 yards.
Based on my observations and work, varmint grade bullets from about 55 grains and down are not what I would put in a SD .223. I will admit that years ago, before a lot of LE and Civilian shooting data with .223 was in existence, I thought a 50 grain Ballistic Tip at about 3000 fps was a good idea, but no more. There are several cases of LE shootings using 55 grain and lighter varmint grade bullets with failures to stop. 60 grain and heavier bullets are what I would look at now. In that realm, there are of course choices.
Light varmint grade bullet failures have been claimed in several cases I have reviewed after someone else did the analysis. I have opined on bullet failures in other cases. In most of those cases, heavy clothing, significant fat, appendages or large bone stopped the bullet. In a few cases, the entrance was on the edge of the torso. In my opinion, with the light varmint grade bullets, they lack the penetration when encountering pretty much anything. In the compilation, the limited set of data I have suggests 55 FMJ ball is a better stopper than varmint grade bullets.
OTOH, the high fragmentation rounds from heavier bullets did not have the same types of failures, and bonded bullets even less. While I agree that the FBI handgun 12" is not a good litmus, I also do not think deer hunting bullets, which we want to mushroom and then exit, are the best answer either.
I can not give you a one-bullet for all answer, and I am not sure that will ever be the case. Another constraint that LE has that a SD does not have is terminal performance at distance. There are some loads being sold to LE that past about 75 to 100 yards have a very high chance of failure due to the bullet design and loss of velocity, others are fine out past 300 yards. Distances and bullet selection are something you will have to evaluate based on your constraints. I do however feel confident in saying that if you use an AR for SD, pick a bullet of at least 60 grains or more.
I have been able to review the ballistic data from several mass shootings as well. Those shot with .223 had the highest death rate. Those shot with buckshot had the highest survival rate. When added together with LE shootings and justified SD shootings, it is clear to me that the .223 is a MUCH better stopper than a handgun which is better than a shotgun with buckshot. 12g slugs and battle (or hunting) rifle calibers are, of course, better than the .223, but they are used so little. I hope this helps some of you.