jdp, the good part about ai'd chambers is, say take a 243 AI, you can shoot regular 243 win ammo in it to make AI'd cases. to rechamber a 243 win to 243 AI, you need to set the barrel back at least .004", the AI chambers are that much shorter than its parent (the neck shoulder junction is .004 shorter on an AI chamber than its factory production parent) hope this helps.
RR
