I've very intently tried to avoid that issue... ... so I could keep more ammo that would work in several guns. This seems to be the best I could do ... and I've stuck to these calilbers. I think rifle calibers is the area that is the hardest to do it. Because then you add in the "type " of bullet (HP, FMJ, etc) .... and geez..... that adds up bad enough.
Handguns : .357 & 9 mm
Rifles : .22, .223, .357, 30-30 & 30-06
Shotguns : 20 ga.