.22 rifles are usually a little finicky about what ammo they like. Your best bet is to re-barrel it, free float the stock, put in a target hammer and increased power spring, and then go out and shoot a bunch of different types of ammo to see what works well in your rifle.

My 10/22 (with the above mods) shoots Wolf match .22LR into one-hole groups at 25 yards all day.