I haven't, but I ruined brass in the beginning by loading too hot. Once I got the load down, it didn't matter much.
What is "coning"?
What brand of brass are you using?
Sorry, I meant coining, like having the ejector or some part of the bolt punch a shape in the back of the brass. I saw it on even the loads I made on the low end of the ladder. I loaded up a ladder of 90gr SGK's using H335 and TAC and it happened on both powders which made me wonder if it was because the brass wasn't fire formed yet.
TAC 28.5gr- 31g
Loaded in new SSA brass