Don't discount a .223 if you find one cheap. You can get a .223 checked to see if it will run as a .223 Wylde, or get it worked to run as a Wylde. Then you can use .223 or 5.56 when you are ready. Always verify the twist rate before you buy.
Down in the Sales area guy was selling a Remington .223 barreled action for like $500, get a KRG for cheap, done deal.
What's your main goal with the rifle??