SKB is absolutely right. .22-250 survived for decades as a wildcat without commercial brass. You will be able to find components or loaded ammo several reincarnations from now. What cal. is best? Depends on many factors such as range, wind levels, acceptable noise level, ricochet danger, etc. I shot 18 groundhogs from the house last summer with a .22 LR Romanian army trainer that will equal a $1000.00 Kimber with cheap Winchester SuperX lead hollow points. Popped one 3 days ago with same gun at 70 yds. with a bullet right in the earhole and that was that. However, I just got a .222 Rem. Contender Carbine barrel as I want something with a little more power and range than the .22, but quieter and more efficient than my .22-250 or 6m/m. My longest kill with the 6m/m was 560 long paces. Then again, I shot many hogs with reduced loads of 50gr. FFG under a patched roundball in an open sighted flintlock where 60 yards was a long shot. Does this answer your question?
