M Die for 45-70

[josper]

I have been using the RCBS 3 Die set for the 45-70 ,using the flaring die to bell case mouths just enough to start the bullet when seating.I have read in another post that alot of guys swear by the lyman M Die.My question is would using this Die be better than what I'm doing.??I'm always open to ideas that will improve the quality of my loads.

[rintinglen]

An M Die probably won't help much in the 45-70, it is more useful in bottle neck and tapered cartridges. Most 45-70 dies are 3 die sets and have ample provision for expanding and flaring the neck. I use one in my 30 cals and in my 38-55, but I 've no use for one in 45-70.

[DLCTEX]

I think any aid to straight seating of the boolit and preventing sizing down the boolit during seating is a plus to accuracy. I would think it particularly would help when using the TL boolits such as Ranch Dog's excellent designs with the micro grooves.

[Larry Gibson]

using the flaring die to bell case mouths just enough to start the bullet when seating

That is the "M die" for that cartridge. Same as the "flaring die" in any 3 die set is the "M die" for that particular cartridge. You can get a generic M die but the only thing it will do differently is allow custom size plugs. Actually I prefer the Lee Expander die that comes with their 45-70 die set as it is easier to make custom expander plugs and even compression plugs as they don't need threading.

Larry Gibson

[btroj]

I use the expander that came with my Lee dies. I can't see a reason for the extra expense of an M-die. Those dies are something I buy for cartridges that don't come with a separate expander.

[Mark Daiute]

The Lee expander die is not the same as flaring the case mouth- it is a full-length expanding die and wonderful for lead boolits in the 45-70

[montana_charlie]

The Lyman M die is a two-diameter expander which sizes the neck of the case to something less than bullet diameter, and has a step which expands just the mouth to something just over bullet diameter.

I think the expander plug in the RCBS 45/70 die set is configured the same way.

If (instead) the set has a 'flaring tool' ... a funnel-shaped expander that wedges the mouth bigger ... a properly shaped slug can be purchased from Buffalo Arms.
The slugs they sell can be had in any combination of diameters you might need for .45 caliber straight walled cases.

CM

[josper]

Thanks for the replies,You cleared that up for me.

[44man]

I don't know if I would use an "M" die for a 45-70 lever gun. Lots of recoil and more case tension is better to hold boolits in the brass in the magazine tube.

[mpmarty]

My RCBS 45/70 three die set has an expander that looks and acts just like an "M" die.

[adrians]

i bougnt a used set of lymans at a gun show the fella was selling the set cheap without the "m" die, he had the "m" selling seperate i convinced him it should be in with the set i bought and he was happy to throw it in for free.
i felt a little guilty for doing that so went by and bought some brass.
use it all the time

[1Shirt]

I like the Lee Universal. Works for everything I load w/cast!
1Shirt!

[trk]

My best accuracy (.405 WIn, .45-70 and .458 WM) with cast plain based bullets is by using an expander similar to the M die.

First, I'll size only the minimum amount.

I turn an expander to just the right size for a tight sliding fit - just enough so I can slide the bullet into the case.

Then I turn down about 1/10 to 2/10ths of it to grip the cast bullet with .002 to .004" grip.

This allows me to put the bullet into the case by hand and to seat to needed depth. Crimping can be used or not.

[Chill Wills]

Interesting to read what all is written here.
For what it is worth: My 35-30 year old RCBS dies are provided with a 0.455" diameter expanding plug- two diameters to flair the case as well. I do not know what the “M” dies are set to (diameter) maybe larger for cast???? I do not have one, I’ve made mine.

With .457" jacketed bullets, that set up might be about right. I replaced mine with one I turned to 0.458" to use with 0.459" bullets. With spring back and crimp I feel like I do get great smokeless accuracy without resizing the bullets when I seat the bullets in the brass.
0.004" neck tension is too hard on the cast bullet and is not necessary. It will size down bullets a little or a lot depending on how hard and how much the difference between case ID and bullet OD. Pull your carefully made bullet some time and see what the diameter is after putting it a small case. Many aftermarket sizer plugs available as has been said.

Just food for thought..