M dies

[mousegunner]

M dies, are they better than the dies that flare the case mouth? I use the flare but just enough to get the lead bullet started then seat and crimp later. It seems the same to me, you either flare or expand the mouth slightly, you're just working the brass differently to seat a bullet.

I also don't see M dies for .223 unless maybe for flat base bullets. I'll buy for .38/357, 9mm, and .45 but looking for feed back. Does it makes a difference or just one more thing to buy? Thanks for looking.

 

[jepp2]

M dies, are they better than the dies that flare the case mouth?

To me they are. Starts the bullet straighter. I only use them on straightwall handgun cartridges, but others use them for a few bottleneck. I generally have used Lyman, but Redding are just fine also.

 

[fatelvis]

They are wonderful. They make placing the bullet into the neck for seating easy and keeps it square before the seating die does its work. It acts as an expander mandrel, creating consistent neck tension and It also eliminates shaving of lead on cast bullets, and scraping of copper on jacketed. Does many things and does them well!

 

[ebb]

whats an M die?

 

[mousegunner]

So if you use one for .223 or any bottle neck do you have to crimp that expanded part down? I chamfer my necks and seat my BTHPs and I'm done, I don't crimp match ammo. I won't get an M die for rifle just curious how that works.

 

[waltk]

They are wonderful. They make placing the bullet into the neck for seating easy and keeps it square before the seating die does its work. It acts as an expander mandrel, creating consistent neck tension and It also eliminates shaving of lead on cast bullets, and scraping of copper on jacketed. Does many things and does them well!

Couldn't have said it better myself. But now I use a Lee die with a "Noe" insert.
These plugs come in various diameters and lengths but are the same "squared" shape
and do the same thing.

 

[fatelvis]

I agree Walt. Lyman were the originators, but NOE perfected it!

 

[Iowa Fox]

I gave up on expander balls maybe 30 plus years ago and started using Lyman M dies. Wouldn't go back. Once you have the die bodies the expanders are less than 10 bucks from Lyman. I can't afford bushing dies or body dies with the Lee collet neck sizer for some of the odd ball low volume stuff I load for not to mention cast bullets where I need the flare.

 

[Uncle Ed]

Below a Lyman type "M" expander for the .223/5.56 and .003 bullet grip. You bump the case mouth onto the .226 section and with brass spring back the mouth will be .001 larger than bullet diameter. This allows the bullet to be seated "straight" into the case by hand and reduce neck runout.

When loading for my AR15 rifles and using bullet with a cannelure and the "M" expander I use the taper crimp die in the set pictured below.

Below the Lyman type "M" expander ensures the bullet is started straight in pistol or rifle cases. You can see the case on the far left has a standard flare and the bullet is resting tilted in the case mouth before seating.

Below the patent for the Lyman type "M" expired and Redding pistol dies now have the type "M" expander.

 

[Intheshop]

Noticeably easier to get the bullet lined up before seating as posted above.

Reason for this post is,the individual "spuds"(just what I always called'm) are an excellent lathe project. I like the Lyman's in this respect. Making several while you're at it gives you the obvious advantage of custom sizes and "range". Just a great way to perfect hitting your "numbers" and finishes..... throw in some process engineering and streamlining.

Good luck with your loading and shooting.

 

[Shaggy357]

Some of the early Lyman "M" dies did not have the taper at the point as shown in Uncle Ed's photo above. I ruined many a case trying to go too fast when loading 38/357 on a single stage press. Case not perfect in the shell holder and accordion would form. I used a grinder to add the taper and polished it to nearly mirror finish. No more accordions. I have used them a lot and really like them.

 

[mousegunner]

I gave up on expander balls maybe 30 plus years ago and started using Lyman M dies. Wouldn't go back. Once you have the die bodies the expanders are less than 10 bucks from Lyman. I can't afford bushing dies or body dies with the Lee collet neck sizer for some of the odd ball low volume stuff I load for not to mention cast bullets where I need the flare.

So I just buy a .45 M die and then get both a 9mm and .38 expander? Sounds good, I'll look into it.

 

[Iowa Fox]

So I just buy a .45 M die and then get both a 9mm and .38 expander? Sounds good, I'll look into it.

yes, unless Lyman has recently changed something I am not aware of.

 

[hoz53]

They are wonderful. They make placing the bullet into the neck for seating easy and keeps it square before the seating die does its work. It acts as an expander mandrel, creating consistent neck tension and It also eliminates shaving of lead on cast bullets, and scraping of copper on jacketed. Does many things and does them well!

i have a set of lyman carbide 44 mag. dies probably. 30 years old at least. havent used them in awhile and i wonder if they have an M die in them ill check thanks

 

[RDA72927]

I've converted several of my M-Die bodies to hold straight expanding mandrels. I order Pin gauges, their around 4 to 6 $, get a 9/16 x 18 bolt. Center drill and add the pin gauge. My last two where a .3075 & .307. For my BRA I have a .2435 that works great for the brass I have.. It's a cheap way for me to try different mandrels to find the neck tension I want...

Robert

 

[Uncle Ed]

I've converted several of my M-Die bodies to hold straight expanding mandrels. I order Pin gauges, their around 4 to 6 $, get a 9/16 x 18 bolt. Center drill and add the pin gauge. My last two where a .3075 & .307. For my BRA I have a .2435 that works great for the brass I have.. It's a cheap way for me to try different mandrels to find the neck tension I want...

Robert

The advantage of the type "M" expander is the larger step that expands the case mouth and aids straight inline seating. And your pin gauge conversion does not have the second larger step or flare the case mouth for cast bullets.

 

[Mad_Charlie]

The advantage of the type "M" expander is the larger step that expands the case mouth and aids straight inline seating. And your pin gauge conversion does not have the second larger step or flare the case mouth for cast bullets.

Easy enough to make if you have the tools and know how.

 

[RDA72927]

The advantage of the type "M" expander is the larger step that expands the case mouth and aids straight inline seating. And your pin gauge conversion does not have the second larger step or flare the case mouth for cast bullets.

I don't use them for cast bullets. I shoot F-Class now and paying 50.00 a mandrel seemed a little dumb. I can make my own for under 10.00 each. I have several mandrels for my 284Win, 6BRA and 300WSM....

Robert