The first barrel I purchased for my G2 was a 30-30, the very next barrel was a 22LR. I handload, and cast my own bullets, so cost is not too much of an issue (about 6 cents or so to load 30-30's). However, banging away with a 30-30 can get tiresome. I shoot my 22LR barrel a LOT during the summer. Lets me get in lots of trigger time.
My 22LR barrel is a 12" Custom Shop bull barrel, has a Nikon Monarch 2-8x scope. Will thread a needle at 50 yards!