I have a question for DocGKR–and anyone else who will weigh in–on the RELATIVE terminal effectiveness of .45 acp compared with .40 S&W. This is not a thread about debating what caliber is better. I am familiar with Doc’s published work, and the principles and results of the “terminal ballistics” work that he and his peers do (including the content on FirearmsTactical.com, TacticalForums.com, and other places). They’ve pretty well established that when you compare modern, high quality defensive ammunition, ALL the service calibers are capable of achieving adequate terminal effects. In addition, they’ve proved that for different kinds of shooting situations such as penetration through intermediate barriers, some calibers outperform others. Terminal effectiveness can even vary by material type, with 9mm ammo penetrating some types of materials better, and .40 or .45 ammo doing better in others (for example, the larger calibers generally perform better than 9mm when fired through windshield glass).
So, my question arises from this context, where you have all the service calibers capable of adequateeffectiveness, but you also see some differences in terminal effectiveness.
Question: Focusing strictly on terminal effectiveness–and excluding external factors such as ammo cost, ammo capacity, or felt recoil, etc.–are there any ballistic reasons to choose .45 acp as a caliber over .40 S&W? Phrased a little differently: What if any would be the terminal ballistics areas in which .45 acp provides a meaningful gain in results over the .40?
Doc, from what you know of wound ballistics testing, how often does the increased “hole” size of the .45 over the .40 make a significant difference in a gun fight? Or, is it simply impossible to tell based on the available info?
Perhaps someone can help me understand how to use the information resulting from answering this question. Is it mostly academic or are there practical applications? If you have freedom of choice of what caliber to choose then the question comes down to your ability to shoot either equally well. This is contrary to my experience. If this experience has wider applicability then it would seem one’s ability to shoot a particular caliber overwhelms any minor differences in wounding ability.
A bit of both actually. I’m really interested in the whole “terminal ballistics” area, the research, etc., including a lot of the practical tests Doc has run on different factory ammo. But it has practical implications too. I haven’t been able to find anything in this area yet, but would like to find, some kind of research that indicates whether the “larger hole” made by a .45 versus a .40 consistently translates into any practical difference in stopping effectiveness. I am interested bottom line in knowing whether there’s any reason in terms of terminal effects to choose the .45 over the .40. It makes a bigger hole, and that’s an excellent reason. Now what I’m wondering is, HOW much difference does that “bigger hole” size make, between the .45 and the .40? I don’t even know if that kind of research is available, but if it is, I’d be interested to read it. I’ve personally chosen the .45 over the .40, but mostly for the more subjective reasons that you often hear. I’m interested to find out if there’s any solid reason based purely on ballistic effectiveness to choose the .45 over the .40. If there’s no MEANINGFUL difference at all, I am seriously interesting in selling off my 45’s (except for my favorite 1911) and converting to .40, because the ammo is so much more available and affordable. And if I’m understanding Doc right, it sounds like the implication is that other than “hole size”, there is not really any other known difference.
how often does the increased “hole” size of the .45 over the .40 make a significant difference in a gun fight? Or, is it simply impossible to tell based on the available info?
No one can answer that question. There is no science that can tell you that .05 increase in bullet diameter produces x% increase in incapacitation certainty. I think it boils down to faith in ones chosen caliber and that the chosen load provides adequate penetration. I should add that the same applies to .45 over .38 / 9MM.
– Cultivate a warrior mindset
– Invest in competent, thorough initial training and then maintain skills with regular ongoing practice
– Acquire a reliable and durable weapon system
– Purchase a consistent, robust performing duty/self-defense load in sufficient quantities (at least 1000 rounds) then STOP worrying about the nuances of handgun ammunition terminal performance.
Pick the platform you shoot best, then decide on caliber from there. Basically all the standard service calibers work when using good quality ammunition; the platform picked tends to dictate the caliber.