Here we go again!
Hands down for me is the 357 Maxi for the only gun. So many variations, so little time. Casting supplies are longer lasting, great versatility in loads from cat sneeze to lion roar.
easiest to find components or ammo with ability to use 3 cartridges and the same dies to reload.
1) 357 Max all around gun from squirrel to deer.
2) 223 Rem long range varminting
3) 12 Gauge bird hunting, close range self defense
4) 45/70 Govt large, dangerous game, vehicular defense/offense
5) 30/30 Win mid range deer/hog/man
All cartridges share at least 2 capabilities
a. common to find components or loaded ammo
b. proven history
c. versatility
d. reliability in a single shot action
There are other things I am sure I can think of, but it's late~