buckstix, my camera is kaputt so only low quality mobil phone pics. I hope you see whats happen.

right original 11,2x60 Schüler cartridge, left brass made from 300 Win Mag
I had to lathe turn the case a little bit because it was to thick in diameter over the base.
then I made a tool for turning the rebated rim in one operation. you see how I used two tools 10mm x 10 mm side by side. one tool grind to make the base with the extractor groove, the other tool to turn the rim diameter. I build a clamp to fix both tools in the right position before chuck them on the carriage.

when done with the tools I take only a file and debur the rim outside in a moment so its ready in one operation.

the other tool for cuting brass on the lathe is my so called "butterknife"

you see I grind it very sharp

it cuts brass very easy but I have also use this to cut steel cases

its no problem at all to cut down brass on the lathe and its so good I will not use the case trimmer after this. rimmed brass will be siting in the notch of the lathe chuck. for rimless brass I have a threaded rod I can adjust from the other side of the chuck, its having a hole for longer workpiece.