I agree with reliability and powerful enough caliber. I define "powerful enough" as 300+ lbs of muzzle energy, for a rough rule of thumb. I would add the .44 Special, .41 and .44 Mag and the 10mm to LBC's list.
Must be able to shoot it rapidly, and make solid hits on multiple targets consistently.
Must be concealable (for us non-uniformed types). This implies that it must be light enough for all day carry, too.
Must have some sort of low-light sights -- most cordite-scented social encounters take place after dark.
Must have adequate capacity. IMHO a five or six shot gun leaves no margin of comfort. I'd accept 7 to 10 rounds if I had to, but as long as I can get hi-caps it's 15 in the gun and 15 in the spare mag. I know that in most encounters only a few shots are fired, but I don't want to survive "most" of them, I want to survive ALL of them.
Finally, must have been cited as the "ultimate" in at least one gun mag. That includes most everything north of a Lorcin.
