I was wrong. I got the 5/16" and they are too big for the Easton Excel 340's. They fit my Beman ICS Hunter 400's, but I'll be underspined if I used them. I guess I could cut some of the Beman's down, but I'm not for sure how much. So for future reference to anyone who buys these, Easton Excels take the 9/32" Axis/HIT's brass inserts.