M1911A1
I used it as a infantryman in SE Asia. After crawling around in rice paddy silt, you shake the big chunks off and it fires EVERYTIME.
As an infantryman the pistol is not for extended us, 7 rounds is more then enough, (though changing mags is quick).
Crawling around in dark slimy stinking tunnels if gives you confidence.
Pistols are more for self protection when long guns aren't practical. For example if you are a Machine Gunner in a place where weapon carry is required, its a lot easier to go through a chow line carrying a pistol then a M-60.
I like the Beretta, mine is extremely reliable but I've never fired it covered with the mud and gunk I've seen on the US M1911A1