I don't have anywhere near 500 rounds of SD put by. My SD stuff is mostly already loaded in magazines.
The closest I come to stocking up on SD stuff is putting a bit more Bullseye under my .45 ACP LSWC bullets. They make a good (i.e.; economical) practice round with normal loads as well as a very good SD round when stiff loaded with Unique.
I have a bunch of .22LR bulk that I've been buying for years, and yup, I shoot it.
The United States Marine Corps: Providing the enemies of America the opportunity to die for their countries since 1775. Semper fi.