I could maybe see the .338 one, since there's nothing comparable, unless you consider the .325 WSM in 8mm to be comparable, but to me it's not because you have poorer bullet choice. Getting a .338-06 and then some performance out of a short action has an appeal.
But the .300 is certainly the question no on asked x 1000. There's already 437 different .300 maggies out there. Regardless, yeah; headed for niche/cult/obsolete quickly, seems to me.
But hey, lookit, even stuff headed for the scrap heap is fine to own and shoot. Even with these "obsolete" cartridges (which these aren't YET), there will always be brass and dies available, at least for the next 75-100 years or more. So go for it, if it appeals to you.
Even after greatly reducing my rifle & chambering lineup to just a few centerfires, I still ended up with one obsolete chambering among them (7mm RSAUM), and I think I'm likely gonna keep it forever. Does what I want and I have the dies -- and brass will always be around from some maker for my lifetime, barring a war/metal shortage.
Well, I suppose that the caveat there possibly worth mentioning is that we *might* just be gearing up for a shooting war if only slowly - the politicians want to drag us into one it seems, via Syria then via Iran, and/or via Ukraine (which will then in turn pull in either Russia or China or both) - I believe it's a slow but steady contrived march to war orchestrated by the banking and oil elites in the USA (primarily the Federal Reserve owners), to try to preserve the petro-dollar (US dollar) as the world standard currency / petroleum currency... China, Russia, and most OPEC nations have a very strong interest in eliminating the petro-dollar, and we have a very strong interest in preserving it (by "we", I mean the owners of the USA's Fed), but that's another topic. Point is, war *might be* where we're in fact headed, gawd forbid. Soooo, that bodes slightly more toward a more standard chambering.
