No offense, but what the f*** kind of question is that?
The kind vague enough to make it borderline unanswerable.
Safe from whom? Skinnys, Gov. both?
For how long do I want to feel safe?
Are we in a shooting war or bugged out in the country?
Will this ammo be used to hunt also?
Will there be a Snake Pliskin-esque run to rescue trapped family in Fall River? (I could theoretically end up in that situation I guess.)
Also I guess I must be pretty silly because I have just OVER 10K 22lr.
Vague answer, 1K min. per cal. per gun that is chambered in it. With some exceptions for special purpose guns that will only hunt, for instance, my 30-30 lever gun. Or things like a 50 cal. or 338 lapua If it's a hot war and or expected to last more than 6 months then double or triple those numbers.