The 204 would probably work if you do some hand loading. Get a good load book and find a recipe that is slower in velocity. I've had excellent results with reduced 223 loading. In my experience, I find that soft points or hollow points are the best on fur. The plastic tipped varmint bullets are very violent and can result in big holes. I find that 700 ft lbs of muzzle energy is the threshold for maximum energy for fur friendly fox shooting. Factory 204 ruger loads can be up to 1300 ftlbs. .