Time after time do I have to sit in between two of my friends who constantly argue over the 9mm vs the .40. ... I am fed up with having them each turn to me and ask which one is better, it's one of those cases where you just gotta get up and lock yourself in another room. So everybody unleash and let me settle this damn thing...
Well, since you asked. Just say they are both wrong. The .45ACP is the king of the defensive pistol calibers. Sgt. York proved it on Oct. 8, 1918. From Wikipedia I quote,
" 'He (York) recalled:
The Germans got us, and they got us right smart. They just stopped us dead in our tracks. Their machine guns were up there on the heights overlooking us and well hidden, and we couldn’t tell for certain where the terrible heavy fire was coming from… And I'm telling you they were shooting straight. Our boys just went down like the long grass before the mowing machine at home. Our attack just faded out… And there we were, lying down, about halfway across [the valley] and those German machine guns and big shells getting us hard.
Under the command of Sergeant Bernard Early, four non-commissioned officers and thirteen privates, including recently promoted Cpl. York, were ordered to infiltrate behind the German lines to take out the machine guns. The group worked their way behind the Germans and overran the headquarters of a German unit, capturing a large group of German soldiers who were preparing a counter-attack against the U.S. troops. Early's men were contending with the prisoners when machine gun fire suddenly peppered the area, killing six Americans: Corp. Murray Savage, and Pvts. Maryan E. Dymowski, Ralph E. Weiler, Fred Waring, William Wins and Walter E. Swanson, and wounding three others, Sgt. Early, Corp. William S. Cutting (aka Otis B. Merrithew), and Pvt. Mario Muzzi. The fire came from German machine guns on the ridge. The loss of the nine put Corporal York in charge of the seven remaining U.S. soldiers, Pvts. Joseph Kornacki, Percy Beardsley, Feodor Sok, Thomas C. Johnson, Michael A. Saccina, Patrick Donohue, and George W. Wills. As his men remained under cover, and guarded the prisoners, York worked his way into position to silence the German machine guns. York recalled:
328th Infantry Regiment of 82nd Division advances in preparation to capture Hill 223 on October 7, 1918.And those machine guns were spitting fire and cutting down the undergrowth all around me something awful. And the Germans were yelling orders. You never heard such a racket in all of your life. I didn't have time to dodge behind a tree or dive into the brush… As soon as the machine guns opened fire on me, I began to exchange shots with them. There were over thirty of them in continuous action, and all I could do was touch the Germans off just as fast as I could. I was sharp shooting… All the time I kept yelling at them to come down. I didn't want to kill any more than I had to. But it was they or I. And I was giving them the best I had.'
York at the hill where his actions earned him the Medal of Honor, three months after the end of World War I, February 7, 1919During the assault, six German soldiers in a trench near York charged him with fixed bayonets. York had fired all the rounds in his rifle, but
drew his pistol and shot all six of the soldiers before they could reach him....."
"Of his deeds, York said to his division commander, General George B. Duncan, in 1919:
"A higher power than man power guided and watched over me and told me what to do."
So the cartridge (.45ACP) and the platform (1911) are proven. The stopping power, reliability and accuracy of both were documented 92 years ago.
The .45ACP/1911 is the unqualified king of defensive cartridges/pistols. No need to use any special ammo. No ifs and buts. The ubiquitous .45 roundnose hardball will do the job, from paper punching to .... thank you very much.