Also, I’m still stuck between whether I am going for a 9 or 45, so I’d be glad to hear what you’ve got on either
This can be a very tribal question, which tends to get people emotionally-driven, identity-oriented answers when you ask around. Think of the truth more as a spectrum of priorities, advantages, and limitations.
I spent about a decade each shooting .45 ACP, .40 S&W, and 9mm, and currently shoot 9mm exclusively for EDC, shifting as I got notable advantages out of each. A big part of that shift has also been the advancements in defensive bullet technology across the last 15 years.
There are pages of details, but the bottom-line points on the cartridge differences are:
- People tend to shoot 9mms more accurately, and more
quickly accurately, than .45s, for the same reason they shoot .22LR and .223/5.56 better than .300 Win Mags.
- Lower recoiling also makes guns more pleasant to shoot, so people shoot more.
- Ammo for 9mm is often half the cost of .45ACP, also leading people to practice more.
- You get more ammo in 1 magazine of 9mm over .45.
- 9mm is often less than half the weight of .45, which is a big deal when you're carrying it miles, or even EDC in some cases.
- The advancements in bullet technology have led to there being, essentially, zero statistical difference in reality-based studies of shootings between the effectiveness of modern 9mm, 40, and .45.
So, bottom line on why 9mm: Quicker accuracy, more ammo, less recoil, identical effectiveness, and cheaper to practice with, leading to overall better shooting performance both immediately and especially over training cycles for the individual.
You'll get guys trying to dismiss any one of these points, but they tend to be stuck in a tribal-identity or binary, black/white thinking with how they argue it. Rather than looking at it as a spectrum of priorities, advantages, and limitations. There's nothing 'wrong' with .40 or .45, they just have different limitations, which matter more or less based on your priorities. I'd be
just fine carrying one of my .45s or 40s into a violent encounter. Absolutely fine. But fine is not high-performance.