From one of Tam's comments:
From a vintage thread at TFL: "Reason To Own A Bunch Of Guns #8: Because if the balloon goes up and you run down to the gun shop and the last thing left on the shelf is a box of 6.5 Arisaka and you don't have anything to shoot it, well, aren't you going to feel pretty foolish?"
Yeah yeah. To stumble upon a crate of 7.62x54 Russian ammo during the zombocalypse and NOT having picked up a single $75 Mosin during the 'before time' would be the height of shadenfreude for the people in the theater watching the zombie movie of my life, wouldn't it? But that has to happen SOMEHOW in every Zombie flick, at any rate, as a major plot point. If it doesn't happen that way it will find some other way to Murphy-kick me in the proverbial groin.
But man it would be nice to have 4 boxes of ammo. One box says pistol and there is nothing but .45 in there, one says shotgun and there is nothing 12 gauge, and one said .22, and one said rifle and you knew there'd only be the one type of whatever it is you shoot. And you or I have more than just 4 guns. Too late now. I am already mixed. At least 8 'types' of ammo, though only a box or 2 for the little-used firearms.