1. If you like to shoot a lot of bullets . . . you can't beat a .22 LR.
2. If you like to shoot a lot of bullets in a defensive situation, and shoot like the average Army or Marine recruit . . . you can't beat a 9mm when shooting FMJ into an enemy that doesn't want to fight you anyway. They'll give right up generally, once you hit 'em a time or three . . . and you can take a prisoner in for interrogation once they get patched up! Or . . . he may sometimes even take a dirt nap before you can interrogate.
3. If you feel you may need a lot of bullets in a defensive situation and shoot like the average LEO recruit . . . you can't beat a .40 Short & Wimpy . . . an ugly, snappy recoil like a downloaded .357mag, but with a heavier bullet that can thump a thug high on drugs and actually stop 'em with good regularity . . . before they can hurt you before bleeding out.
4 If you are an experienced handgunner who shoots well and is confident of your abilities to put a shot exactly where you want it virually every time, a long barreled derringer in .45ACP would do you well!!! Then again, since they ain't being made, you might be forced to get one that holds between 6-8 rounds.
The benefits of the .45ACP? WONDERFUL accuracy. A hard-thumpin' bullet that can weigh twice the weight of some 9mm ammo. Best of all, the most wonderful "feeling" strong-push type of recoil that makes it so much fun to shoot easily.
5. If you bowl with 16 lb. bowling balls simply because no one makes a 20 pounder, get a 10mm . . . It shoots the .40cal bullet of the 40S&W . . . but at a very fast velocity too . . . which is devastating on deer sized animals and humans alike.
However, the kick, noise blast and the muzzle flip will mean that you will get beaten in a fast gun fight if you miss with the first round and are going against someone shooting a .45ACP.
BOTTOM LINE . . . for the best "Thump" for the "Bump" (hitting power vs. recoil severity and time to recover for additional shots) . . . the .45ACP has nearly 100 years of puttin' the BGs down HARD.
Most of us old farts who have been shooting for decades prefer the single action speed and short, surgically precise trigger pulls of the 1911 autos in .45ACP . . . especially after seeing what wins with great regularity in pistol matches we watch AND compete in.
Folks who haven't competed a lot may share other views, of course . . . but if you hone your skills well enough to "put it on the line" (the competition "firing line" that is), you'll become a huge .45ACP fan generally!
This is especially true when you shoot "steel" matches where heavy metal plates and poppers must be knocked down . . . and knocked down with devastating authority. The 9mm is in a different class . . . for it is wimpy on plates and on heavy metal poppers a 9mm may not always put 'em down when you hit 'em well. The .40S&W does "ok," and the 10mm recoils too much to engage multiple steel targets and knock 'em all down the fastest. The .45ACP does it with authority and in the fastest total times!
ON the street, I want the same results . . . the most THUMP in the shortest time between engaging multiple targets. If I can't do it in six to eight shots . . . I'll do a very fast reload and keep going.
Then again, most gunfights last 3 seconds or less. You want the hardest THUMPS you can get with the fastest recoil recover times.
.45ACP . . . all the way! It is the best "fighting" caliber for effective punch vs. speed.
T.