RE: 22-250 or .223
.223 would serve you well in most cases. If you are going to really get into varmint hunting, and want longer range, or plan to reload then you might go with the 22-250. I would figure out how much you can afford for your gun and scope, and plan on 1/2 toward gun and 1/2 or more toward scope, that should narrow your choices and then let personal preference dictate from there.