The rimfire ammo availability problem doesn't seem to be improving very much. However, I recently discovered a unique website that helped me locate a supply of high quality (Federal) bulk-packed .22LR. The site is billed as an "ammunition search engine," and it's called ammoseek.com. There's a link at the top of the home page for their listing of .22LR ammo.
If the lack of ammo is preventing you from participating in the NVSA rimfire matches, I suggest you give ammoseek.com a try.