Is 9mm really less effective than .45 ACP?
The eternal debate: Which cartridge is more effective? 9mm or .45. On the face of it, .45 seems like the obvious choice. However, if you take one of our classes (like General Defensive Handgun) you will realize you can’t use caliber to make up for poor shooting. The bullets just aren’t that big!
Occasionally, a student will mention some “horror story” he/she read or was told involving a bad guy who soaked up 20, 30 or more 9mm rounds and how you never hear about that happening with a .45. Or they will quote some “1 shot stop” book’s studies. By the time you’re done reading this post you should be able to figure out for yourself the usefulness of that material.
I believe there is a non-ballistic answer that can explain some (certainly not all though) of this discrepancy. So this post is going to largely ignore what we know from terminal ballistics and, instead, conduct a little thought experiment that should be illustrative of why you need to be so careful when reading about guns and self-defense.
We will use two hypothetical guns/shooters: Shooter #1 – The 1911 .45 ACP with 7 rd GI magazines. Shooter #2 – The Glock 17 9mm P with 17 rd magazines.
In our thought-experiment, we are going to shoot a bad guy (BG) who is posing a deadly threat towards us. We will assume he is reasonably motivated and doesn’t just quit upon seeing our gun. We will assume that our first shot is a mortal wound to the heart (thus subsequent shots are largely irrelevant). We will assume that there are no spinal hits or effective head shots (which, regardless of caliber, would be instantly incapacitating and so pointless to consider).
Common wisdom is that properly adrenalized and motivated individuals can continue to function for up to 15 seconds with a fatally damaged heart. We will also assume that the shooters can both shoot 3 rounds per second (0.33 splits) and their reload times are 3 seconds.
In our first case, we will assume the BG drops in just 5 seconds. In this instance Shooter #1 (1911) will shoot 7 rounds. Shooter #2 will shoot 16.
Yes, the Glock 17 shooter shoots more than twice as many rounds! Remember, this is with the first round being a fatal though not instantly incapacitating wound. What happens if the BG drops in just 3 seconds? Shooter 1 gets off 7 rounds (still) and Shooter #2 shoots “only” 10. Still 40% more rounds! And 3 seconds is pretty quick!
Of course, I picked one of the most extreme cases, just to wake you up. As you lengthen the time to stop, the discrepancy in percentage terms drops but the round count differential still can be rather large. For example, 10 seconds to stop but with 8rd 1911 magazine instead of the 7rd. Shooter #1 shoots 16, Shooter #2 shoots 23. That’s down to +44% more, but +7 in the round count. Note that the 7rd shooter would only have shot 14 in this case!
If you assume a slower reload, say you have duty gear, the differential gets less still. Add in a 4 second instead of a 3 second reload and you have shooter #1 shooting 16 and shooter #2 shooting 20. But that’s still +4 rounds.
In all cases except extremely short times and/or very slow shooting, the larger the magazine, the more rounds you’re going to fire to stop the BG in the exact same timeframe. However, this isn’t an endorsement towards high-capacity magazines! The BG stops in the same amount of time regardless of how many rounds you fire. It’s simply that the shooter with the high-capacity gun is going to shoot more rounds in the same amount of time due to the frictional costs of having to reload more often.
The take away point is this: Round count is largely meaningless as a predictor of cartridge effectiveness without a lot more context. So take what “statistics” you read or hear about regarding self-defense and ammunition with a huge grain of salt!
I don’t think there are any meaningful statistics being gathered about shootings to date. There are far more variables than simply “1-shot stops” or even total number of shots – imagine two Glock 17 shooters against 1 BG in comparison to a lone 1911 shooter – what will the round count discrepancy be in that case?