Hi S,
I use a RCBS #10 in my Rock Chucker for 32 S&W brass & some Nagant brass. I think it is a 223 case holder. The cases vary form one co to another.
I have a second RCBS of the other Nagant brass. Can't find it at the moment.
EDIT 7 AM Hi, i found it! It is marked #7 no other marks. I think it is a Lee as it is not finished like a RCBS. It fits hot shot brass like it was made for it.
I just brought a few various brand cases to the gun show & bought what fit.
I wrote down a note in the M-1 die box, used the Dillon 550 B press with a D shell plate & locator button 3 . I made a bunch so it must have worked.
Please check BEFORE you buy anything. Check your reloaders web site. Send them a message they are very good about quick replys.
Best to you,
point6