I had the same issues with WW 308 brass Kurt. It worked fine when going from 308 to 338, but RO was pretty wild as the exp was doing all the work. Once fire formed, the exp doesnt touch and bullets just fall in the case. Fed 338 Fed brass works like a champ, but it has thicker necks. I tried some Fed 7-08 brass I had on hand and got the same results as the 308 WW cases, useless after FFing. Now, I've picked up some Fed 308 brass to try. It has a touch thicker neck than the 7-08 brass, so it may work.