Also, the bullets were moly but I tumbled them to get the moly off...not sure if that would make any difference...I don't think it would...

A too-light charge of slow-burning powder can cause the symptoms you report as well as too much powder. It takes over 65,000 PSI to blow primers. I can't recommend shooting any more of the loads that gave you this result! Best to start over!

Well my Dad shot some .270 WSM today (2.5gr below max load, new brass) and he also blew half a dozen or so primers...I'm kinda thinking we got a bad lot of primers...??