USMCPMI
I usually use Imperial Sizing wax too, BUT for the BMG cases it will result in a lot of stuck cases for me, Try mobil 1 fully synthetic motor oil, I use the 5w-30 wt and haven't had a stuck case since, just got done resizing 50 cases last night, I had fired all of them thru either my AR50 or my old Serbu BFG50 and I tried to use the Imperial wax first thinking it would be ok cause it wasn't machine gun brass that had over expanded, but it was not going so good and I switched to the Mobil 1 and the difference in force necessary to full length resize the cases was phenominal, the Mobil 1 makes the resizing just too easy, give it a try and you'll see.
keith