I'm guessing you were reloading 338 Lapua Mag with Hornady brass. With the 338 Lapua, you have to use different shell holders with different brass. The #14 works with Lapua brass but not with Hornady or other brands. With these other brass, the extracter groove slope hits the lip of the shell holder before the base of the case hits the bottom of the shell holder, putting pressure on the lips. This eventually breaks the lips.
If I'm completely off base, ignore this post.