Ok, here's what I did. I tried the turn and rechamber thing with several of this batch of brass and no go. then I dug through my cans of 1, 2 and 3 times fired brass and it all chambered no problem. I took a few of the others and neck sized them and tried again and they again chambered no problem. It seems to be this one bunch of once reloaded Winchester brass, all fired the same day, that is giving the problem. Got me wondering fer sure. I do know I was firing some warm loads that day and had a buddy at the target with a radio so not much cool down time. What do you think of the hot chamber theory? Its about all I can think of right now. I miked the brass compared to others and I can only see a few thou. diff. in certain areas. The webs are all the same, just the bodys are .002 different. ****, these custom chambers are fussy.