M Dies

[BIGRED]

I have a 35 caliber short M die i use for my 35 rem. can i also use this for 380 / 9mm? i have had great luck with the standard bell die with my 380, 9mm and 45 acp. i needed the M die for the 35. but is it really necessary for all pistol and rifle using cast. my loads all work flawless, so the whole "not broke don't fix" issue is making me think i may not need them.

[GabbyM]

Lots of variables. Especially with 9x19mm brass. I use a 122 gain TC bullet a lot for 9mm. It seats deeper than a 124gr RN bullet. My Dillon powder through expander doesn’t go very deep in a 9mm case. With some brass it doesn’t matter due to the case wall tapering out. Other brands of brass have walls that get thicker and will swag the bullet down to look like a boat tail. So I use the M die in Station one of the Dillon in place of the size die. Of course have to size brass first. But I do that anyway then tumble clean off the lube. Last year I got set up to load 38 Special. So have a 38/357 powder through die that is longer. Some have said those work well in the Dillon on 9mm brass. I do load a .357” cast bullet in my 9mm. I’ll have to give it a try. My guess is it will work on some brass but not others. Whatever it takes to get it done.

[bhn22]

Have you tried it to see if it will work? I'd be concerned about the length of the neck expander, 9mm uses a really, really short expander because of the internal case taper.

[BIGRED]

Have not tried it. my loads shoot very well and there is no resizing or shaving of the boolit. so i am pretty sure i may not need an M die. for my 35 rem, yes i needed it.

[454PB]

What GabbyM said. If you're not swaging the boolit down when it's seated, you don't need an "M" die. I made an "M" die for use with 9mm because I was swaging certain boolits.

[ACrowe25]

Have not tried it. my loads shoot very well and there is no resizing or shaving of the boolit. so i am pretty sure i may not need an M die. for my 35 rem, yes i needed it.

Yep, don't need to make it more complicated than it is--- unless neded. Lol

[Char-Gar]

The Lyman M die and the other makes (RCBS etc.) do the same thing, i.e. expand the case neck to accept the bullets and open up the case mouth so the bullet won't shave lead as it enters. The only difference is the M die opens up the case mouth with an opening with parallel side and the others flair/bell the case mouth.

I tend to prefer the M die for one reason and one reason only, I can place the bullet into the opening at the case mouth and it will stay there and not rock around like it does on a flair. That probably doesn't make any difference in the final loaded round.

Bottom line, is the M die is not magic, but just an alternate design to a case expanding plug.

[GabbyM]

Have you tried it to see if it will work? I'd be concerned about the length of the neck expander, 9mm uses a really, really short expander because of the internal case taper.

Not tried it yet. My guess is the 38/357 Dillon powder through expander will indeed bottom out in some 9mm cases. But work in others. I stopped loading mixed head stamp 9mm about thirty years ago. Have to load up 9mm, 38 Special and 357 mag within a week. Have a full USPS flat rate box of mixed 9mm. IIRC it's 3,000 pieces. The fun potential of sitting with a magnifying glass and sorting all that almost overwhelms me.

[BIGRED]

I feel your pain, i hand sort every case by headstamp. even though i use a progressive press i prefer to deprime totally separate from the rest of my loading, i do the same with priming. every case after it is deprimed goes through a case gauge and once again after it is loaded. i touch the brass way more than most people but i want to make sure i have Zero issues with my loads.