Well, by "oddball," I meant pretty much any of the calibers other than the 4-5 most common handgun calibers and the 2 most common rifle calibers. 10mm, .357 SIG, and .38 super would probably be the most commonly available of the non-standard autoloader cartridges, while most wheelie cartridges other than .38 and maybe .357 fit that profile. Probably not much tougher to get .44 special or .41 magnum or .327H&R today than in November. In rifle cartridges, the last few gun shows I attended suggested that getting .270 Winchester or .45-70 is little harder than usual. IOW, as long as you've got something OTHER than the things people pick because they expected to ALWAYS find ammo, things are inconvenient but not impossible to get.
All this ammo and component shortage cr@p will blow over eventually, but in the meantime, diversity is your friend.
Whether some common platform is best is another discussion. But I think the same lesson applies. Standardizing on, say, a Glock sounds good until there is for some reason a shortage of Glock parts. Think about the logistics and industrial infrastructure that nations have adopted during prolonged, total war. A single manufacturing plant for all barrels, or all ball bearings, or all engine blocks, is simple. It's also vulnerable to disruption. Simplicity is the absence of redundancies. Redundancies are how you make a system more stable.
