I use a small pill bottle that is the right size ,anything round and not steel that is the right size .
Just roll up some heavy wieght foil around it about 3 wraps ,tape it closed I then slip the tube of foil of the mandral(pill bottle) part way then fold the foil over against the bottle bottom and tape then pull the foil off the mandrel . Load it with powder ,the fold over the open end and tape .
Gary
Ill take a few pics and post