One problem with the .22 caliber cartridges is that they are not legal in all states or in Canada for big game. If you're looking for one rifle to 'do-it-all' consider that and how available is the cartridge if you loose the ones you are carrying: airline, theft, dropped overboard on the transfer from the float plane to boat...etc
Any corner hardware store, garage, general store I have been in in remote areas that sell ammunition, usually has the more common .308, .270, .30-06, 7mm RM, .300 WM on the shelf. Other stuff not so much.
Good luck
Jerry