RE: 22-250 or 223
Both are very accrate rounds. You couldn't go wrong with either. I personally have a 22-250 and it shoots very good 1/2" 5 shots groups or smaller, if I do can do my part. That said, I think that the 223 is easier to get that kind of accuracy from though. Will you be reloading or using factory ammo? If your reloading there is not much difference. The 223 is cheaper to reload though.
Good Luck.
Doug