Today I modified a .303 British sizing die to size the .38-50 cases. I cut the dies shoulder and it still had some material at the taper and I did not ream the cut yet. I ran a case through to check the diameter and I found that slight taper is sharp enough that when the case was pushed all the way in and extracted it made a uniform cut reducing the wall thickness one thousand per side or two thousands combined. It is a very good neck shining cut better than I could use a neck trimmer. I have a notion leaving it as it for this use and get another $17. lee do this again for the sizing die so I can run the case all the way down to the rim to swage the base. But the cases are just fine for the DDPP 371-345 bullet so I will ream the cut.
This is turning out to be a fun project.