sscoyote,
I don't have any experience with either one, but had Dan Carey do a barrel for my AR, in 17-223. It shoots little tiny groups, I think there are pictures on one of my previous posts. Cases are simple to make just run a 223 case into die and done, I bought my Hornady dies through Lock, Stock, and Barrel for $49.95, and they work great. Just something to think about vs. the other chamberings you asked about. Target pic is titled New Arrival - Target pics +.
BoomSplat