Thread: Oh no. Why?

Had a go with some 180eldm in the 7mm rem mag today. Second shot with starting load @ 65.5gr 2217 the case came out in 2 pieces. Nothing out of the ordinary happened after pulling the trigger other than the impact was way off.
Fired 20 other rounds and all fired good. Brass was bought as "once fired" and this was the 3rd fire.
Failed brass?