I'm using a 223 lee collet die for my new 223ai. Using the 223 lee seater die also. I have a lot of groups with two in one hole and one flyer off to the side opening the group up. I think that a better seating die might help. I don't have anyway to measure run out. What sweater die is best for 223ai.
Redding comp says cannot be used with compressed loads.
If the hornady gauge shows lots of run out and I cant correct it I will try the redding seating die.
Redding makes a great seater die (great sizing dies also) but it wont straighten out crooked necks, most run-out issues are caused by the sizing process.....you might want to start with a Redding bushing die