Our cartridge work and experimenting got a nice
write up in # 470 Nov/Dec International Ammunition
Journal. Page 10-11 by Zach Weighman, a
cartridge collector and gun nut friend.

Got a guy just figured out BMG case rim, and for a rim
puts on 12ga high base cup from a plastic case. He turns
base/rim of bmg case about .008" and use JB Kwik to hold
it on. Pushes it on with press. He removes base cup with
heat gun from plastic cases,

He is using RE17, so shotgun primers will work, and he
puts bushing in case for primer. Has bushing reamed so
the primer pocket protrusion on the base cup goes up inside
tight, as he pushes on the base cup. It'll fire ok and to size it
do like I do, I push case into open top die, and push it
back out from the top with a rod and hammer. That
way the rim don't get bent up. He says it saves a lot of
time not having to make rim pieces.

We will have more info and pictures next few weeks.Ed