You can get a compression die from Buffalo Arms. Shiloh sells a good compression die as does Midway. Or if you have and extra "M" die body you can just buy just the stem, some folks take a bolt with the proper thread and turn the head down to the diameter needed. If you have a quality set of dies such as from Lyman, RCBS, or Saeco, the expander die can be set to compress the powder to the desired depth.
