Tweeter, you are comparing two different animals. The 223 short mag is a factory gun, and the 22/250 AI HAS to be a custom chamber.
All of the 22/250 AI's that I have had with the 15,14, or 12 tiwsts have been very easy to work up extremely accurate loads with.
I have only worked with one Win Stealth in 223 super short mag and had really good luck with 60g bullets and h380.
Good luck!