I have found that the amount of ammo that you can afford is probably the best reply to the question. I have failed in that at least one time; back when we could get 8mm for pennies I only bought a few thousand rounds... I have regretted it ever since. Remember that some calibers will become harder to get ammo for. I remember the day when we thought we were getting ripped off for 7.62x39 at $70.00 , and last month I purchased 3k rounds at $179.00 per case... it could well be that the ammo will dry up as it did for the 8mm or rise significantly like the .223 or other rounds.
MOLON LABE !!!!!
They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety. --Benjemin Franklin
A fear of weapons is a sign of retarded sexual and emotional maturity. -- Sigmund Freud
TO vote for the lesser of two evils , is to still vote for evil.