I would suggest a good 223. Ammo is really cheap and its fun to shoot with no recoil to worry about. I use one for varmit hunting out to 300 yards or so. Cheap ammo is available everywhere. Its a centerfire not a rimfire so you will get the feel of a real rifle. Savage and Remington are brands that I have owned in that caliber as well as the Ruger. Hope this helps.