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Lyman M Die

Discussion in 'Handloading and Reloading' started by fourdollarbill, Sep 3, 2010.

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  1. fourdollarbill

    fourdollarbill Member

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    The Lyman M Die advertisment claims to be different than the other dies that just expand the case and flare the end. But the M die description explained that it expands the case and flares the neck.
    Whats up with the M die and why is it more usefull?
     
  2. loadedround

    loadedround Member

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    The Lyman M die was designed to expand (flare) the case mouth of rifle cases to accept a cast bullet without shaving lead. It is very similar to the expander die in a pistol set. The expansion is somewhat controlled by how deep you screw in the expander button. The M die does not size the cartridge case. I own two M dies for loading cast lead bullets in my 375 H&H and 45-70 Spfd rifles. Many of my friends also use this die to load cast bullets in their 30-30's.
     
  3. rcmodel

    rcmodel Member in memoriam

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    Yep.

    The M-die flairs and/or bells rifle cases for lead bullets in the same way a pistol die set does.

    Your regular rifle sizing die pulls the expander plug through the neck on the way out. It cannot flair or bell.

    The M-die expands and/or bells on the way in.

    rc
     
  4. Jim Watson

    Jim Watson Member

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    The M die does not apply a conical flare like the bugle mouth commonly seen on pistol brass, it puts a little step in the mouth of the brass. Makes it easy to align and start the bullet.
     
  5. GooseGestapo

    GooseGestapo Member

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    The M-die not only flares the case mouth, but expands the entire case neck as it has an extended stem. This is helpful because it alighns the neck and the bullet when seated, is seated in a truer alighnment with the bore of the firearm. Sometimes when seating a bullet, the bullet can enter the case mouth slightly out of alignment and will contiue to be seated out of alighnment as the bullet is forced deeper, inducing a large amount of run-out.

    I've found that seating all my .22Hornet ammo after running it through the M-die significantly improves the accuracy, even with jacketed bullets. I stumbled onto this by reloading some Hornet brass with jacketed bullets after I had expanded some brass anticipatiing loading them with cast bullets. I was astonished at the accuracy of that "batch" of ammo, and was able to attribute it to the "expanded" neck brass.

    The Lee "Universal Expander" die is useful, but it dosen't completely match the utility of the M-die.
     
  6. Gryffydd

    Gryffydd Member

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    What Jim said. I use Lynan M dies for all my pistol reloading. I like the way bullets practically snap into the case.
     
  7. Walkalong

    Walkalong Moderator

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    Another big +1 for the design. (Which Redding copied)
     
  8. Offfhand

    Offfhand Member

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    Mr Goose gives a pretty good description of the M die and it's proper use. It is NOT simply a die to flare the mouth of a rifle case like a pistol case, as some inexpert comments (from above) apparently assume.
     
  9. rcmodel

    rcmodel Member in memoriam

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  10. USSR

    USSR Member

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    Great Die! I use one for loading the little .30 Carbine bullets.

    Don
     
  11. Asherdan

    Asherdan Member

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    Of course not.

    But then they don't skip (A) and (B) like some of our resident experts.

    The important feature difference between the M die and a standard expand/flare die is as already described in posts #4 & 5..
     
  12. Walkalong

    Walkalong Moderator

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    The Lyman "M" Die, as I see it.

    Excel sheet "Pic" attached

    Exactly
    .
     

    Attached Files:

    Last edited: Sep 3, 2010
  13. Lee Roder

    Lee Roder Member

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    Exactly. It really is the best thing since sliced bread. The bullets kind of "snap in" place and won't seat crooked, like they sometimes do if they are a little fatter than normal (lead) using a standard conical flare. I bought a hornady die with a sleave which supposedly would have helped my alignmnent problem at about the same time I learned of the M die, but it's not really useful after the M-die. Well worth having.

    I haven't used it for anything but 158gr SWC so my only experience with it has been with lead bullets. If it helps for jacketed (which are slightly narrower) in the same way, lemme know!

    :D
     
  14. Runningman

    Runningman Member

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    Started using the M die back in the 80s after reading about in the ABC of Reloading. Works excellent for using lead bullets, most all pistol cases, or other thin wall cases. One of the big advantages of the M die is not over working the brass neck as typically happens in standard neck flare. M die is self limiting and does not change "flare" diameter with variations in case length like a typical flaring expanding die will do. It also helps line up the bullet so it feeds in straighter. Since your working the brass necks less, neck split cases decrease.

    Guess I don't think flare is the correct term to use since it does not flare the case per se like you would think of in other reloading expanding type dies. Nor does the flare resemble a flare type fitting used in plumbing such as some fuel and hydraulic lines.

    The M die more or less forms 2 steps using 3 steps on the expander. The lower step is usually .002 - .0025 smaller than the bullet diameter. The next step is usually .002 - .0025 bigger than the bullet diameter. The 3rd step on the expander is basically a hard stop.
     
    Last edited: Sep 3, 2010
  15. ranger335v

    ranger335v Member

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    The third step on my M dies is a flaring cone so I can flare or not as I wish by a simple tweek of adjustment. Thing is, set correctly, it's rarely needed or even helpful to actually flare a case when using those expanders.

    I use them for both rifle and pistol, cast and jacketed because their use slightly reduces runout compaired to any conventional expander. Redding has copied the M expander design for their handgun die sets.
     
  16. Jwbfx4

    Jwbfx4 Member

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    The above posts explains it real well.

    I purchased a M die a while back in .45 colt. I definitely would recommend it, it makes starting the bullet straighter a lot easier.
     
  17. steve4102

    steve4102 Member

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    OK, dumb questions, but if the "M" die expands the neck in step one and flares the mouth in step two don't you reduce the much needed neck tension? In the rifle die, how do you remove the flare? With handgun ammo it's the crimp die, but what about the rifle flare? I could see maybe setting up the seating die to apply a slight taper crimp to remove the flare, but many of my Comp/Custom seaters do not have a crimp feature.
     
  18. loadedround

    loadedround Member

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    Offhand'S quote:
    "Mr Goose gives a pretty good description of the M die and it's proper use. It is NOT simply a die to flare the mouth of a rifle case like a pistol case, as
    some inexpert comments (from above) apparently assume"

    I SINCERELY HOPE YOU ARE NOT REFERRING TO ME AS SOME ''INEXPERT'' RELOADER. iF YOU HAD I TAKE EXCEPTION TO TO YOUR COMMENT AND HOPE A MODERATOR PICKS UP ON YOUR COMMENT/ATTACK!
     
  19. PO2Hammer

    PO2Hammer Member

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    With cases like the 30-30 that's a big advantage as it slows down the lengthening of the cases over time. I ground off the expander bell on my 30-30 dies so there's no pull at all on the way out of the case.
    There's still plenty of neck tension. Either expanding method leaves the case neck about the same size, depending on the exact diameter of the bell or the M die stem. You could always reduce the diameter of the stem with a drill and sandpaper.
    I use the Lee factory crimp die.
     
  20. ranger335v

    ranger335v Member

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    Steve, #17: " if the "M" die expands the neck in step one and flares the mouth in step two don't you reduce the much needed neck tension? In the rifle die, how do you remove the flare? With handgun ammo it's the crimp die, but what about the rifle flare?"

    Good question but the answer is simple; when it's used correctly there is very little "flare" from the M die. The expander plug's major diameter is of "normal" diameter for the caliber. At the upper end of that portion is a second, very short (about 1/16" or less), section that's no more than maybe 3 thou larger than normal bullet diameter. Adjusted to the case mouth, it expands sufficent to allow a square bullet heel to enter the case and sit straight up and bullets won't be cut during entry. But there is little or no visible flare at all. After seating, you may chamber and fire the round in most chambers without concern for crimping or removing the tiny bit of over expansion.

    The plug's third step is a flaring cone that lies immediately above the second step. It allows us to "bell" the cases if we wish but unless a bullet is MUCH larger than normal no belling is needed or even helpful.

    Crimping is a personal choice, it's rarely as important as some seem to assume. When crimping IS needed and your seater doesn't have a crimp ring a seperate crimping die is the only answer. In the opinion of most of us who use them, Lee's various Factory Crimp Dies are the best available.


    A thought: Perhaps it would be best if we don't wear our egos externally and search for vague personal insults when none is given?
     
    Last edited: Sep 4, 2010
  21. fourdollarbill

    fourdollarbill Member

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    Untill I seen the side cut out description on the link above I was uncertain. I pic is worth a thousand words.

    I would assume there is no special seating die to close that expansion But is there one better than another for this M die application.
     
  22. steve4102

    steve4102 Member

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    Thanks Ranger, I have Redding 45 ACP expander die that I have never used, thought it would open up the entire neck too much, Time to give it a try.
     
  23. Walkalong

    Walkalong Moderator

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    I use the Redding expander (which is basically a copy of the Lyman design) on my .45 ACP loads. Works great. For jacketed and plated I set it up so the second step just does go in the cases enough for a bullet to barely start go in, getting it straight to start its journey seating. I have a Redding or Lyman expander for almost all my die sets. Great design.
     
  24. ReloaderFred

    ReloaderFred Member

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    I love the Lyman "M" dies, but found that they can't be used on new Starline .38 Special brass without some type of inside lube. The brass has no lubrication as it comes from Starline and sticks to the "M" die as if welded. After pulling two cases completely apart, with the top of the case stuck solidly on the "M" die mandrel, I did a couple of things.

    First, I cut off the stuck piece of brass and I polished the mandrel with Flitz until I could literally see my reflection in it, but the very next new case stuck solidly to the mandrel and the case was visibly stretched by the time I got it withdrawn and there was once again brass flecks stuck to the mandrel. I then decided it was time to try another method, so I tumbled the new brass for about an hour and that put some lubrication, or residue, on the inside of the cases and allowed the use of that die and brass combination. The other thing was to go back to using a standard expander die with new Starline brass.

    Now I see that Starline has a FAQ concerning this issue on their website.

    I didn't mean to high jack the thread, but only wanted to let others know of my experience with this brass and die combination.

    Hope this helps.

    Fred
     
  25. ironhead7544

    ironhead7544 Member

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    I use the M die for all my rifle loads now. I always hated pulling the expander through the neck. When I set up a progressive for 223 I decided to use the M die to make thins run smoother. The size die is set up with just a decapper, no expander ball. Works like a charm. Its an extra step but worth it.
     
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