Lyman M die

[Frank]

What is the size of the expander on a Lyman M die? Less than bullet diameter? How much?

[noylj]

Going to make your own?
What one has to do is expand a case and compare the case ID to the expander. New, soft cases have little spring back while work-hardened cases will have spring back
What you want, ideally, is the case ID to be 0.001" less than bullet diameter.
Thus, for lead bullets, you may need a couple of expanders to achieve ideal expansion.
Go to http://www.lasc.us/Brennan_LymanMDies.htm
for dimensions.

[dromia]

There is a Lyman "M" die sticky at the top of this forum with "M" die dimensions in it.