Why not just get a Tompson Contender carbine? You can get 16" barrels in .22LR all the way up to .45-70. Those two barrels should take care of what needs done. Changing barrles involes 5 minutes and a screwdriver. The Tompson Encore will handle higher pressures.....308, .30-06, etc. but I am not sure if they offer a .22LR in the Encore but I can't imagine why not. Both guns can be had in pistol or rifle configuration, and can be switched back and forth by adding or removing the rifle stock. Just remember, if you have a rifle stock on the firearm, it MUST have a 16" or longer barrel to be legal.