"M" die ????

[XWrench3]

ok, i have a couple of questions about these. first, for a 300 win mag, i think i need a 30L "M" die, correct? second, this is strictly an expander, right? it does not size the neck back down, correct? third, what are the diameters of the sizing part? it looks like there are 2 different diameters on the Lyman website. i need to know before i order one if it will open it up so a .311" bullet will fit into the case neck. thanks!

[arkypete]

Xwrench

You are correct the 'M' die expamds the case neck after sizing and puts flare on the case mouth for seating cast bullets.
I always polish down the neck expanding portion with crocus cloth, leaving the flaring portion as is. think of it as accelerated wear so there's less effort required to expand the neck.

Jim

[TCFAN]

For my 30 cal. I always buy the 31 short or long M die.The 30L or short works better with .308 or .309 dia. boolits and the 31 works better for .310-.312 dia. at least for me....Terry

[462]

The first diameter of my 31R plug measures .3095", and the 30R measures .3065". The second diameters measure .0045"" larger. For the .30" calibers, I use the 31R.

The first diameter sizes the case body, while the second expands (not flares) the case mouth and allows the boolit to sit squarely in the case mouth.

Forum member Buckshot makes custom plugs, to your specifications.