Where I am, the cartridge caliber for handguns that Wal Mart always seemed to have was 9mm. They spent a solid year without 45, 40, or 380. They had some 38 and 357 from time to time. It wasn't til 3 months ago that I started seeing 45 and 40 caliber. They still don't have 380 (though I don't have any 380s, but I hear the 380 owners complain still when I go in for my fishing stuff). And for rifles, they always had 22 caliber and shotgun (12 and 16 ga) ammo.
If guns were outlawed, then only outlaws would have guns.