A prime example for having several rifles in different calibers. In my case, I have a AK74 in 545x39, a MAS49/56 in 308. and a M1D in 3006. I have LOTS of ammo for all three. At my age, I doubt if I will ever shoot all of it up. If you are worried about running out of a particular caliber, BUY MORE IF IT. All it takes is money.....Oh, if you would quit bump firing, you would have more ammo.....chris3