If I drop to only 1,000 for a gun, it means I'm out. No more shooting until I get more. Kinda like that money that's in the checking, but doesn't show on the ledger. That is a 1,000/gun minimum not 1,000/caliber.
With some guns(like my 444 marlin, or my 30-30)I'll never have more than 1500 rounds on hand. Other guns(like my ar15's and ak47s) if I'm under 10,000 I'm not really happy. With 22 rimfire, it's more by a ways.
I'm one of those that fit right in the middle. More on hand than most, but the ones that do keep more than I do around, keep A LOT more.