Can I expand a 7.62 case neck to take a .312 boolit with a Lyman M Die?

[Gray Fox]

I just cast a batch of Lee .312-185-1R to load for my Ishapore 2A1. I'm going to size them to .312 and what I'd like to know is if a Lyman M Die will expand a case neck enough to allow seating a boolit that diameter? The next question, of course, is if it is possible, what happens when I run that case and boolit through a normal Lee seating die? Will it just try to size it back to normal diameter? All input will be appreciated. GF

[EDG]

You would need an expander spud about .311 to .3115 diameter.
Lyman can tell you if they have an M die that size.
If you are using a Lee sizer you can guy the Lee expander for a .303 sizer and put it in your .308 die body.

[Mk42gunner]

Yes, the commonly recommended one is the 31R. I myself use the M-die that came my .32 ACP/ S&W Long die set, with the spud installed in a rifle length expander body. One of these days when I am flush I will order enough M-dies for all my different calibers; mixing and matching, while it works, is such a PITA.

Seating the boolit shouldn't change your diameter, at least it doesn't in my old sets of RCBS dies.

Robert

[geargnasher]

31R. The Lee tool only bells the mouth, it doesn't expand the whole neck if that's what you need.

Gear

[o6Patient]

If you get the bullet started I think the case neck will expand the extra couple thou.
I fire-lapped a 30-06 25 years ago and I'm quite sure I used .311 100 grain slugs to do so.
If I'm remembering correctly they went right in(??).
The 7.62x39 should be a couple thou bigger than the o6 to start with, again if I'm remembering
correctly.:???:

[WyrTwister]

I load .311" - .312" cast bullets in .30-30 . Lee dies , I use the expander from a .303 or 7.62 x 54R . The the Lee universal expander die in the next station to give the mouth a slight bell . This makes it easier to start the cast bullet .

God bless
Wyr