Help with Lyman "M" case expansion die.

[Greenjoytj]

I have a Lyman "M" case expansion die. Am I supposed to use it when loading jacketed bullets?
I'm loading 38 spl. & 357 mag in Starline cases.
So far I loaded and fired a few hundred cartridges without using the M die, I just seated the Hornady HP 158 gr. XTP bullet in the sized cases. Sometimes I get a very small copper shaving during bullet seating. Maybe a slight case mouth flaring would prevent shaving a little copper?

Now I've tried loading cast lead (BHN ~ 15) .358" dia. 158grs SWC bevel base bullets. I used the M die, but only about 3/16" of the expansion tip was inserted into the case mouth. I could easily stand and seat a BB bullet into the case mouth with just this small amount flaring/expansion.
I did this slight amount of expansion so the cases wouldn't get over worked plus the BB bullet seated easily.
Now I'm worried that the case grip maybe so strong that the lead may get squeezed to a smaller diameter if the ctgs. sit around for a few months.
My sizing die is a Redding duel ring carbide and it really grips the Hornady bullet. I broke my RCBS Kinect bullet puller trying nudge a bullet out a few thou. and the Hornady cam lock puller squashed a XTP to a SWC shape and still the bullet didn't budge.
So any M die advice on when & how deep to expand cases would be appreciated.

 

[BLUEDOT37]

I added the Lyman "M" expander die to all the cartridges I reload. I originally got it for cast bullets but have now switched to plated (& some coated cast) instead & like it for them too. (I use a taper crimp on all my plated bullet handloads.)

The "M" die has a longer expander plug, & adds a stepped mouth, which I think works best with (softer) bullets you don't want to deform.

When I load copper jacketed bullets, like the XTPs you mentioned, I use the standard expander die from that set (usually a Lee) as it's depth is shallower. I add just enough flare to get the base of the bullet started (you shouldn't get any shavings when you seat it) & let it expand the case "to fit" so it'll have maximum bullet-case tension as these are typically for full/magnum loads.

I wouldn't sweat overworking the case mouth as long as you only add enough flare to get the bullet started & not shave lead/copper. Roll crimps probably do more to shorten case life than expanding does.

.

 

[rwsmith]

I haven't used one in a while....

...but I believe that if you push it in a bit deeper, it does flare the mouth of the case. You should not get shaving.

 

[Forrest r]

I see the wearing out brass thing posted a lot. That should be the last thing on any reloaders mind. The end result is your making low quality ammo but on the bright side . You can make more of it because your brass will last longer.

Myself, I load 38spl/357's until they split. Get 60,80,100??? reloads out of a case. I'm not sure how many reloads I get per case but I do remember buying 1000 357 cases back in 1985 and add to that range pickups. Finely tossed everything and started over last year and bought 2000 new starline cases.

The m-die is designed to protect the base of the bullet & to start them straight in the cases.



Typically I use the factory expander die for jacketed bullets and the m-die for lead/coated bullets. Neck tension means different things to different reloaders. Is neck tension on a bullet important? Absolutely!!! But a consistent even pressured neck tension is more important.

Consistency ='s accuracy
Some bugholes with plinking loads in a 357. I have 9 or 10 different loads that range from mild (pictured bellow) to wild that will chew bugholes in paper.


Worry about hitting what your aiming at, if you have to buy new brass every 20 or 30 years it's called the cost of doing business.

 

[2152hq]

On straight walled cases, like most pistol cases reloaded w/ a standard 3 die set, I really don't see an advantage of using a specialty M die.
The standard expander of the die set is nothing more than the M die profile
It enters the mouth of the sized case and expands it to the correct dia,,pushing it in further will produce and degree of flare you desire to the case mouth. All exactly what a separate M die does.


Where the M die does work to advantage are with bottle neck cases.
In these, FL sizer die is also the neck expander.
On the withdrawl of the case from the die the expander 'button' is pulled through the reduced dia neck (due to resizing).
This motion upsizes the reduced neck dia to the final internal dia needed for seating. Standard FL resizing stuff.

What the M die was supposed to provide was for shooters to size the case with out the expander button being in place.
The next step was to use the M die to open the neck up to final dia & put a flare in the mouth if desired for easier seating of cast bullets.
Many reloaders felt the brass lasted longer & didn't stretch the case using the M die instead of the expander button. Lyman marketed them on that premise too.

The M die was originally put out there for cast bullet rifle shooters. It was the 3rd die needed to make a 2 die rifle caliber set easier to load cast bullets.
(Put a smaller dia expander button in the FL die and it'll still decap, but not expand)



Just the way I see it.

 

[BruceM]

The "M" die should be set to expand and flare the case mouth the same whether you are using cast, coated or jacketed bullets with flat, boattail or bevel bases. The case mouth should be flared just enough to start a standard flat base bullet into the case. A bevel base or boattail is not a substitute for proper flaring.

The "M" style expander is most useful for loading cast or swaged lead and coated lead bullets but is perfectly suitable for plated and jacketed bullets so multiple expanders are not necessary. It prevents shaving during the seating process and aids a significant amount in seating bullets straight into the case.

In the case of bottle neck rifle expanders, the interior of the case neck should be lubricated to prevent pulling the case's shoulder back out when removing the expander. There are also carbide replacement expanders made which greatly reduce this problem.

Bruce

 

[noylj]

The M-die comes with the normal expander section, a larger expander section that should make the case ID over that short distance large enough that the bullet just sits in it, and a flare section.
If you are loading jacketed bullets, the standard M-die works fine. If you bullet does not sit in the case, you either aren't expanding down enough or you need a slightly larger expander.
For lead bullets, I have ALWAYS needed a larger expander than the normal one and order what I need.
If you get brass shavings, that usually means that you have never chamfered the case mouth inside and out and you are scrapping off the burred edge.

 

[BLUEDOT37]

I'll echo what noylj mentioned about new brass needing to be deburred/chamfered as this is seldom brought up.

All newly manufactured pistol brass has a burr around the inside edge of the case mouth than can be felt with the tip of your little finger/fingernail. A light deburring/chamfering is needed to remove it before seating a bullet.

At the same time I do this I usually take the opportunity to give the primer pocket a quick twist with the nose of the deburr tool to chamfer the primer pocket opening to insure easy seating.

.

 

[eo1bart]

I use the "M" die for all my lead pistol bullets. If you have one I advise that you dissemble it, remove the expander and apply loctite to the threads, because the expander WILL eventually loosen up and cause erratic case mouth flaring.

 

[jaymoore]

You can get too much "grip" on lead projectiles! Most die sets currently made are set up for jacketed bullets and may size down lead bullets below optimal. I've long since gone to "homemade" expanders for lead bullets, especially swaged. Increases accuracy and minimizes to eliminates leading.

Try some "cowboy" dies for loading lead bullets if you don't have a way to get expanders made like you want 'em.