Picked up a set of .300 win mag dies at the gun show today. Reloaded some nosler partition accubonds with it tonight in 200 gr. 30 cal. in various powder loads to test for pressure before looking for accuaracy later. I'm using new winchester cases. About half of the loads (some low charges and some higher) the neck shows minor waves or ribs running circular around - not lengthwise.
Any idea what is causing this? Should I be concerned about firing the rounds? They are not for my gun but I'd hate to lose a good hunting partner. :-)