Lee Universal Expander vs Lyman M

Not open for further replies.


Nov 9, 2006
I recently started handloading cast bullets for .30-.30. I bought the Lee Universal case expander die and it seems to work great. But I've heard that the Lyman M die works the brass less. I know that the Lee expander die bells the mouth, and the Lyman M enlarges the whole mouth. Do you prefer one expander die over the other, and why? Thanks.
Lyman "M" die compared to the Lee Universal Case Expanding Die

Having only used the "M" die, i would guess if the long neck body has been expanded by a standard die, Lee's should open the mouth just fine. I never had to crimp the rounds in 30-30 or 30-06 to get rid of to much bell using the "M" die. Lee/Midwayusa >
Gently flares the case mouth to accept cast bullets without shaving. Works great to prevent damaging the moly and low friction coatings found on today's high performance bullets. Tapered expander plug is designed to flare the case mouth for use with cast lead bullets. Includes neck plugs for 22 through 45 caliber. Works on everything from the 22 Hornet to the largest Ultra Magnum. Shellholder sold separately. Works in any press that accepts 7/8"-14 threaded dies
If brass is not trimmed to the same length, looks like the Lee "might" bell some brass to much or to little. :confused:
It should be noted that the following calibers use a handgun decapper and they do not expand the neck of the case.

30 M1
38-55 Winchester
375 Winchester
45-70 Government
44-40 Winchester
444 Marlin
For these you would need a Lee Powder through expander die, maybe? :confused: My Lyman works, its been around longer then Lee, why change? Lee would seem to be a better investment as it works with all callibers. Lyman only works with a few if that.
Last edited:
http://www.midwayusa.com/viewproduct/?productnumber=409943 Cast bullet diameters for a 30-30 are sized to .310" for the most part. The Lyman "M" may open the inside of the neck body more than a standard die expander. Taking measurements is the only way to know. A hard alloy will not be sized by the brass on loading, but soft just might make a difference. http://www.lymanproducts.com/lyman/dies/rifle-die-details.php?brand=3&cartridge=26&die=52 Lymans claim >
. Doesn't stretch cases as does standard expander button.
This would seem to be true, but the amount of stretch is very small over many loadings. This is why we trim brass.
Last edited:
I've been using the Lyman die on my 357 Herrett (think 35 Remington) for shooting cast bullets. Lately I've been using it for jacketed bullets but I back off the expander plug so it doesn't flare the case as deeply. Never tried the Lee.
When to use a"M" die ??

I use a "M" die when I use plain based boolits so the nice sharp corners on the base are`nt rounded during seating !

I do`nt worry as much when seating GCed boolits ,which is mainly rifle , I use the lee expander

& as with all expanders, seaters & crimpers A consistent length helps!
I prefer the M die type, whether Lyman or Redding, for plated and jacketed. I tend to use the standard expanders for lead. I do not want to run the M die far enough in the case to get a bell for the lead.
Thanks for all the good information everyone. I think I'll just stick with the Lee then, since I'll mostly be using cast bullets with gas checks. It doesn't sound like the Lyman M die would be much of an advantage for my needs.
Lee's is a "universal", Lyman's is caliber specific. As in most such things, a general purpose tool works but not as nicely as a specific purpose tool.
Lyman "M" die

I use the Lyman "M" die for 7.62x54R, .30-30, .35 Rem, .358 Win, 7x57 Mauser, 8x57 Mauser, .303 Brit, .45-70, and .458 Win Mag.
For my reloading, I have found that I achieve greater accuracy utilizing this die as the entire neck is enlarged when I set the die to allow only slight flaring of the case mouth.
This allows for better bullet alignment and gives less run out when placed in the co-ax indicator.
Not open for further replies.