Lyman M die

[Matt Anthony]

Removing post for personal reasons!
Matt

[Hefights]

Supposedly designed for seating cast bullets. So does use of the M die on jacketed bullets have a noted improvement in concentricity as opposed to what competition sizing and seating dies can already affect?

[p246]

I use M dies for loading cast. In that respect they have been great.

[nf1e]

I use both the Sinclair on the left and Lyman M on the right neck expanders before neck turning. I find the Sinclair a little easier to use and way easier to change calibers.



Semper Fi
Art

[bigedp51]

Supposedly designed for seating cast bullets. So does use of the M die on jacketed bullets have a noted improvement in concentricity as opposed to what competition sizing and seating dies can already affect?

Using the Lyman type "M" die expander with jacketed bullets you expand the neck slightly on to the second larger step but not to the point of flaring the case mouth. This allows the jacketed bullet to be started straight into the case neck easily without tilting and inducing neck runout. I have read this is popular when using progressive presses when loading for the AR15 or M1/M1A. As you can see above the lower section of the expander is .003 smaller than bullet diameter and gives plenty of bullet grip for semi-autos.