"But magazine capacity aside, I can't think of what advantage the 40sw has over the 45acp."
DEANIMATOR: Maybe the font was too small. I just spent two paragraphs acknowledging that for some people, magazine capacity seems to be important. Are you saying that you can't think of anything else either?
Demko; no one said the 40sw failed. This thread was started because someone believed that there were obvious advantages having the 40sw over having 45acp. I personally can not find any such advantages. Magazine count has never and WILL NEVER be an issue for me. I have said that for offensive uses such as law enforcement and the like, that magazine capacity is definitely a consideration. I don't believe it's an issue with civilians; however; I do recognize that there are some that feel more comfortable having the extra rounds. And perception is truth, so that's acknowledged.
As for the advantage of the 45acp, the 2 that I believe are most important; especially for those who aren't the most proficient with a gun; is that the 45acp is 10% bigger in bullet diameter and 15% in bullet weight. This means more damage to the person you shot. Don't get me wrong, I'm not a firm believer that bigger is always better. For those who are proficient, accuracy can be MORE deadly. That's why I have no problem carrying a 32acp or 9mm makarov as concealed carry in the summer months. But, if I couldn't carry concealed; and open carry was the only method; then I'd either carry my P220 45acp or my S&W model 13-1 357 magnum revolver.
And I'm definitely not dogging the 40sw. Personally, I don't really like any of the in between semi-auto calibers. Most are niche calibers or developed strictly for economic reasons. This includes the 10mm, 357sig, 327, 45gap. etc... I prefer military and LE calibers because they went through some of the best testing in their time and some of the best modifications as needed since then. In my opinion, for the person that can ONLY have ONE GUN, the choice is pretty simple. (Again, my opinion). For a semi-auto, a 9mm. I personally don't care for it, but it is definitely tried and true. And with modern day ammunition, you can cover a variety of uses and needs. This military caliber is reliable and effective. Ammo is readily available and inexpensive. If the choice was a revolver, then the choice would be a 357 magnum. With it's ability to also shoot 38 specials, the bullet weight, powder, velocity, and energy combinations are such that you can find a 357 magnum load that can equal any other hand gun with the exception of the 41/44 magnum or the hunting handgun monster rounds like the 454/460/480/etc...
But for me, I believe that NO pistol caliber is optimum for self defense. Therefor we have to make up for it's shortcomings with training, practice, and accuracy. 95% of CIVILIAN self defense using a hand gun never ever has to even pull the trigger. The mere presence of the gun is usually enough t stop the threat. The other 5 percent of the time, it's not a "Gun Fight" anywhere similar to what a police officer or similar would go through. But if a person believe that even a 0.000001% chance that it could be, warrants a 15-18 round magazine, then more power to them. But that same argument says you should have another 15-18 round magazine on you; as well as maybe a couple boxes of ammo in your pocket. Obviously, there's got to be a balance between purpose, practicality and paranoia. We have all read articles and reports where a person was shot multiple times with a 44 magnum and kept coming and even survived. And we've read articles and reports where a person dies from a single 22LR bullet.
The laws of physics says that the larger the bullet; the more it expand; and the more physical damage it can do; the better it is for self defense. However; sometimes that large weapon isn't practical. And because ALL handguns are inefficient as for self defense, there isn't a major drop in efficiency by using a 32/380/9mm for the times where the bigger gun isn't practical. And because there isn't a gun out there in 45acp that isn't basically the same size as any 40sw you can find, there becomes no advantage to having the 40sw. (Other than magazine capacity). The 45acp can do everything the 40sw can, YET with a BIGGER hole and MORE damage; and it does it with LESS kick and discomfort to the shooter. So; if you're going to carry the BIGGER guns because you want maximum tissue damage to the bad guy, then you use a 45acp. If however, you don't feel comfortable with 8 rounds in a gun; then you COMPROMISE, and get a 40sw with a 15-18 round magazine. And if you ARE COMFORTABLE with your abilities to shoot effectively, then you get ANY CALIBER HANDGUN you want that fits you perfectly. Maybe it's a glock 19 or a 21. Maybe it's a 1911A1 or a Sig P220. Maybe it's S&W 686 revolver. Maybe it's a Walther 32 or 380 PPK. In my opinion, because ALL handguns have shortcomings for self defense, the priority of choosing a gun should be:
1. Gun that fits PERFECTLY in your hands. Balance, weight, sights, ergonomics, overall feel comfortable.
2. Gun that fits the carrying purpose. Either concealed, open, non at all (For home use).
3. Gun that is comfortable in operation. If you rarely if ever shoot, and realize that adrenaline and stress are going to kick in during an actual shooting, consider a revolver that doesn't require as much "What If" knowledge. "POINT AND CLICK". Or consider the semi-auto if you're willing to practice a lot and become proficient so that the inevitable FUBAR can be corrected automatically.
4. Caliber that is the most comfortable for you to shoot. There's a lot of of weights/grains/velocities in numerous calibers. Find one that the "Average" plinking ammo is comfortable to shoot. When the time comes for actual use, you don't want a caliber/ammo that your brain is already telling you subconsciously that it's going to be uncomfortable. This caliber could be 32, 380, 9mm, 40sw, 45acp, etc...
5. And finally; if you are still so unsure or not confident in your abilities; but you practice enough that semi-autos are a practical choice; then you could prioritize the high capacity choices like the 9mm or 40sw.