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NVcurmudgeon
01-09-2006, 02:30 AM
I expand my rifle cast boolit cases with RCBS expander dies. They have been very satisfactory. RCBS expanders go from the equivalent of Lyman's long step into a funnel-shaped expander. So that I can make a comparison between the RCBS expanders and Lyman two-step M dies could somebody post the diameters of both steps of Lyman M dies in the following caibers: 7mm, .30, .32/8mm, and .35? TIA

utk
01-09-2006, 06:14 AM
NVcurmudgeon, I've found this table somewhere:
(The proper formatting seems to "get lost". PM me with your addy for a Word doc)

begin*********************************************

M" Die dimensions from Lyman

Diameters +.0000
-.0005

Rifle Plugs..First Step/Second Step..Bullet sizes

22R .222 / .225 .222-.226
24R .242 / .246 .243-.244
25R .255 / .259 .256-.257
26R .262 / .266 .263-.265
27R .276 / .280 .277-.279
28R .282 / .286 .283-.285
30R .307 / .311 .308-.310
31R .310 / .314 .311-.313
31AR .318 / .322 .319-.321
32R .320 / .324 .321-.323
33R .337 / .341 .338-.340
35R .357 / .361 .358-.360
37R .374 / .378 .375-.377
45R .455 / .459 .456-.458

Pistol Plugs

25AP .249 / .253 .251
30P .307 / .311 .308-.310
32AP .310 / .314 .311-.313
32P .313 / .317 .314-.316
38AP .353 / .357 .354-.356
38P .356 / .360 .357-.359
10mm .398 / .402 .399-.401
41MP .408 / .412 .409-.411
44MP .427 / .431 .428-.430
45AP .450 / .454 .451-.453
45P .453 / .457 .454-.456

"M1" and "M2" Expander Bodies

Rifle Caliber Use with

M1 M2

17 Rem X
22 Hornet X
22-250 Rem X
.220 Swift X
.222 Rem X
.222 Rem Mag X
.223 Rem X
.243 Win X
6mm Rem X
.25-20 X
.25-06 X
.250 Sav X
257 Roberts X
6.5 x 55 X
.270 Win X
7mm-08 X
7-30 Waters X
7mm Rem Mag X
7mm Weath. Mag X
7mm x 57 X
280 Rem X
30 MI X
30-30 Win X
300 Sav X
308 Win X
30-06 X
300 Win Mag X
300 Weath Mag X
7.62 x 39 X
.32-20 X
303 Brit X
32 Win Spc X
8mm x 57 X
8mm Rem Mag X
338 Win Mag X
35 Rem X
358 Win X
35 Whelen X
375 H & H X
38-55 X
444 Marlin X
45-70 X


How are these dimensions related to the 'steps' above?

The main shaft of the expander portion is the "First Step". It
is typically a few thousandths smaller than bullet diameter, as
are conventional expander buttons.

The "Second Step" puts a small step of increased radius in the
case mouth about 1/16th inch deep (adjustable). This step is a
few thousandths over bullet diameter to aid effortless starting.

What are expander bodies?

The die bodies that hold the expander plugs; directly analogous
with conventional expander dies.

See the Lyman catalog for a picture which is worth a thousand
words.

How much expansion or bell does the M plug put on the case mouth?

Ideally, for lead bullets, the first step would be about .002"
under bullet diameter. For jacketed bullets, the first step
should be .003-.004" under bullet diameter. In either instance,
the second step will be 2, 3, or 4 thousandths over bullet
diameter.

Usually the best lead bullet diameter is about .0005" less than
the chamber's measured throat. Most of my .30 caliber rifles
shoot .310" or .311" cast bullets best. I keep several plugs on
hand and have a machinist friend turn them to my specs if I think
it will help.

It is also highly desirable, on a two diameter rifle bullet, for
the nose of the bullet to be of bore riding diameter. To check
this for a given bullet, push the bullet nose first into the
rifle's muzzle. If it goes in without resistance, the bullet
nose is too small and good accuracy is not as likely.

Does the seating die crimp out the bell or do you just leave
the cases expanded?

Your choice. For my lever actions I sometimes crimp. For bolt
actions, I do not.

*********************************************end

NVcurmudgeon
01-09-2006, 11:47 AM
utk, thank you very much for your prompt and comprehensive answer. You have even answered the questions that I didn't know enough to ask! Now to get busy measuring my RCBS expanders and then probably pick up an M die in one caliber for testing. I'm always looking for ways to refine my better loads.

versifier
01-09-2006, 01:56 PM
NVc, I have a .30 M die that I've been using for years and have no complaints with, but I think I'm going to go with the Lee Universal unit the next new caliber I move on to. Most of the reports on them I have read have been favorable.

utk
01-09-2006, 05:22 PM
utk, thank you very much for your prompt and comprehensive answer. You have even answered the questions that I didn't know enough to ask! Now to get busy measuring my RCBS expanders and then probably pick up an M die in one caliber for testing. I'm always looking for ways to refine my better loads.



Glad to have been able to help you!
How about posting the measurements of your RCBS expanders? I'm kind of interested in those, don't quite like the sharp step in Lyman's M expanders...

Urban

MGySgt
01-09-2006, 10:48 PM
For those that are interested - Lyman also sells special size M die plugs in certain calibers. Can't find them posted any where, but I calledthem awhile ago and bought one for Cast 45 rifle. It expands to .458 vice .455 for larger cast bullets. I was told when I called about it, we created it just for you guys that shoot Cast.

FWIW

Drew

NVcurmudgeon
01-10-2006, 05:13 PM
I have measured my few RCBS expander die plugs and come up with these measurements:

Nominal diameter Actual diameter
.28 .2837
.310 .3095
.311 .3105
.323 .3227
.358 .3574

The sizing part of the plug is .500" in length, with the exception of the .28 plug which is .400". The plug then tapers at 45 degrees until it reaches the diameter of the material the plug is made from. The .310, .311, .323, and .358 are made from a .500" piece of steel, and the .28 from .375".

I looked at the RCBS web site and noticed that they offer only one expander plug in each caliber, and that the nominal diameters are the nominal diameters of jacketed bullets in that caliber. The only exception is .30 caliber, in which caliber RCBS lists .308, .309, .310, and .311 diameter. Looking at the actual difference between the nominal .310 and .311 sizes, I wonder why they bother!

This has been an interesting study. If RCBS practice on my selection of expanding dies holds true for the rest of the sizes, the only apparent benefit from using them over the normal expander plugs found in their loading dies, is the 45 degree neck flare, which does prevent the case mouth from scraping the cast bullet while seating. Adjust these dies very slowly and carefully lest you produce a funnel-mouthed case that will not enter your seating die, or a full-length split neck.

If your reason for for using RCBS expander dies is to prevent sizing your cast bullets down in the case necks, you may be spinning your wheels, except in .30 caliber.

Four Fingers of Death
01-11-2006, 06:12 AM
After several decades of reloading, I have ended up with a few M dies spare as i don't use them on pistol reloading (I use Lee powder measures virtually exclusively for charging pistol cases as it saves a step on my Rockchucker).

I thought of machining some 357 M dies down to suit 303 and 30 cal lead boolit loads, but my mate (with the lathe) won't have a bar of it, reckons they are too hard. Is this the case?

MGySgt
01-11-2006, 07:03 PM
I thought of machining some 357 M dies down to suit 303 and 30 cal lead boolit loads, but my mate (with the lathe) won't have a bar of it, reckons they are too hard. Is this the case?
FWIW
The die body is real hard - but the expander plug? I don't think it is. Try a draw file on one (that you are willing to sacrifice) and see how hard it is. I will bet that it isn't as hard as we figure it is.

Drew

Four Fingers of Death
01-12-2006, 06:55 AM
Thats about what I thought. Funny though the new dimension Hornady ones seemed to be cast as a single piece. They would be hard as, but you couldnt get in to machine hem anyway.

utk
01-12-2006, 10:30 AM
I think Hornady's expander plugs are press-fitted into the body, perhaps with the help of Mr Loctite.
You could probably drill a hole from the top and tap the plug out with a drift punch?
The die body itself isn't too hard, I've shortened one in the lathe and also turned down the top end to make the threads "grippable" in the chuck.
However, if the plug is a press-fit, that end is probably tapered so it could be difficult to get a hold on in the chuck anyway.

Urban

Cherokee
01-12-2006, 01:27 PM
I've tried the Lyman plugs with carbide cuter in the Lathe and the ones I have are Very Hard.

MGySgt
01-12-2006, 07:38 PM
Thanks for that info Cherokee - I was thinking of polishing down a 45 Rifle to give more expansion in a 44 mag when I size to .432.

You just saved me some real frustration!

Drew

MattOrgan
04-04-2011, 06:30 PM
Four Fingers of Death: If your friend has a lathe, just have him make the entire plug. I made one for my .416 Rigby 10 or 12 years ago out of mild steel. I've used it maybe 200 times with perfect success. I always clean the inside of the neck and lubed them slightly. If you want to get fancy use oil or water hardening drill rod. The Lyman parts are harder than woodpecker lips.

Reverend Recoil
04-05-2011, 11:05 PM
For the 9.3x57, 9.3x62, and 9.3x74R riflemen.

Lyman 9.3mm M-die: 0.362" / 0.388"

nanuk
04-28-2011, 11:41 PM
for my 9.3, I bought a .375 RCBS off ebay...

gonna try to reduce it using sandpaper in a drill press.

I had read in the past that the Mdie for the 9.3 was not cast friendly. but I have not found one yet anyway

I do have some larger ones that I may get some rod lathed down. I was thinking Gr5 bolts with a long shank. I heard they are 9/16. can't remember the thread pitch.

Reverend Recoil
04-30-2011, 03:44 PM
Both Lyman and RCBS make a neck expanding die for 9.3mm cast bullets. Hornady and Redding may make one as well.

Pigslayer
12-20-2011, 08:47 PM
[smilie=w:Just ordered a Lyman "M" 31L Die for my 7.62 x 54R. Should work O.K. if not I can change the plug. Just started shooting my Mosin with jacketed last week and am gearing up to go cast. Next step . . . a mold from Accurate!!!

40Super
12-30-2011, 07:25 PM
If anyone wants some expanders I will make you one on my cnc ,can be for any die or caliber.I just need the make of the die and some general demensions ,but can make them to whatever size needed. More than one and I can make them cheaper. PM me with any requests

popper
03-06-2012, 05:00 PM
I turned one down with 400 emory on a flat plate and a drill motor, didn't take long for .002.

Char-Gar
09-25-2012, 12:24 PM
Some notes on case neck expanders;

There were a number of difference M-type die expanders used for the Lyman 310 system. Many of them are much better for cast bullets than the current Lyman production. Ex: 38/357 available in .357 and .358. 45 hangun in .452 and .454. Various 30 caliber sizes from .308 to .313.

I have a new set of RCBS expanders from .308 to .311. Two measure dead nuts on, and two are .0002 undersize (not enough to matter)

tacotime
11-14-2013, 12:24 PM
Note also the RCBS Cowboy expander for cast usage, marked as .358, although the first step measured .356 on my mic and as noted by another guy before...

rhwinger
04-29-2014, 05:54 PM
Hello. New to the site and so far reloaded about 800 Colt 45's. Recently bought some cast bullets 0.453" and 0.454". Heard about the Lyman M die, so it's now part of my tool kit.

Only problem is, the OD of the expander plug is 0.452, but when I run it into a case, it produces a 0.457" ID case mouth opening and the bullets just drop right in. This is BEFORE I get to what I call the secondary shoulder at the top of the die where the case is further expanded for the bullet to fit without lead shavings.

Any ideas on what I might be doing wrong? I called Lyman and they insist it's the right expander plug.

Or am I just stuck with trying to find a machinist to turn the plug down.

Thanks in advance for any suggestions.

Thanks,

Bob

Ben
04-29-2014, 06:11 PM
Bob

Something is BAD wrong here.

Let's go over this slow....

(1) you're sizing your brass in a full length sizing die, correct ?

(2) I'm sorry , but a .452 outside dia. can't produce a .457 " opening in the end of a case. Theoretically impossible.

Brass has " spring back ", if you put a .452 " expander in a sized .45 Long Colt case, it should leave you with a .451 or .4505 " opening in the end of the case.

Sounds like you may be running the M die , expander plug too deep into your sized cases.

These measurements that you're offering, are you getting these with a dial caliper or a good micrometer ?

Ben

JonB_in_Glencoe
04-29-2014, 06:11 PM
Hello. New to the site and so far reloaded about 800 Colt 45's. Recently bought some cast bullets 0.453" and 0.454". Heard about the Lyman M die, so it's now part of my tool kit.

Only problem is, the OD of the expander plug is 0.452, but when I run it into a case, it produces a 0.457" ID case mouth opening and the bullets just drop right in. This is BEFORE I get to what I call the secondary shoulder at the top of the die where the case is further expanded for the bullet to fit without lead shavings.

Any ideas on what I might be doing wrong? I called Lyman and they insist it's the right expander plug.

Or am I just stuck with trying to find a machinist to turn the plug down.

Thanks in advance for any suggestions.

Thanks,

Bob

Did you measure this ?

rhwinger
04-30-2014, 07:22 AM
Ben/JonB:

I am neck sizing with Lee sizing die in an attempt to minimize case hardening. May have to rethink this as I experienced some jamming when trying to load cartridges into the chamber of my Ranch Hand last weekend.

Measured with digital caliper. When I measure 0.453 and 0.454 Dardas cast bullets, I get 0.453 and 0.454. The only "known reference" I have.

I am inserting expander plug just past the end of the rounded taper, to where the plug just starts to straighten out. The bullet seating shoulder is WAY past the end of the rounded taper, up near the end of the plug where it attaches to the die body. At least that is what I *think* is the seating shoulder.

In any event, no matter what the caliper says, the bullets just drop into the case mouth?

Thanks guys.

Bob

MGySgt
04-30-2014, 09:18 AM
Does your expander plug have 45 R on the end of it? (the actual plug where it goes into the case first).

I believe you have the Rifle expander vice the Pistol Expander. The pistol one has 45 P on it.

JonB_in_Glencoe
04-30-2014, 09:38 AM
well, if you measure the expander plug and it's 0.452, and then measure the ID of the neck (not just the case mouth) and it measures 0.457

Then something else is wrong...maybe your technique...maybe a worn wobbly press ?

It's tough to diagnose over the interwebs...Honestly it sounds impossible.

edited:
PS, what does the ID of the neck measure before expanding with the M die ? as you said, you are using a Neck only sizer die...Maybe you don't have that adjusted correctly...did you read the instructions ?

CastingFool
04-30-2014, 09:51 AM
Does your expander plug have 45 R on the end of it? (the actual plug where it goes into the case first).

I believe you have the Rifle expander vice the Pistol Expander. The pistol one has 45 P on it.


That's what I was thinking, too!

rhwinger
05-01-2014, 11:11 AM
45 P on the plug.

It's a fairly new (2 years old) Lee Classic 4 hole press. It does have a little slop in the action, but always has?

I am neck sizing by inserting the case into the standard resizing die about 3/8 - 1/2 inch. I'll try a full length casing resize to see if anything changes. Who knows?

This is so strange. I must be doing something wrong. Thanks for all your suggestions.

New to the site and enjoying the helpful folks here.

Thanks,

Bob

EDG
04-01-2015, 05:25 PM
Here are the measurements for a new Lyman 50-70 M die plug.

This plug is marked on the end 50 R

This plug is a little different than most rifle plugs. It has 3 diameters close to the bullet diameter.

.510 diameter - this is the first diameter into the case but its effective length is only .250 long. It looks like a large auto pistol expander it is so short.

.5145 - this is the step that we are used to and it is .080 long. This step could be polished out to make the first step longer then you can polish down the top step to just over your bullet diameter.

.5175 - This is not a functional diameter on most M dies but it might help some rifles with oversize bores or you can do some polishing to make the effective lengths and diameters longer or larger. This diameter is .215 long and is the top end of the plug.

For my use I should have made my own M die expander.

44magLeo
01-30-2019, 02:32 PM
I've been searching Lyman M die expander plugs.
I have found a few things that might help. I hope I can post my purloined pics.
In the first pic it shows A die cut away that tells how far the case should be pushed up onto the M expander plug. The second pic shows it with more detail.
The second The case at A is expanded to the minor size of the plug, just under bullet diameter. B shows the case pushed just up onto the step. This expands the end of the case to just over the bullet diameter. About 1/16 inch is plenty. Just enough so the bullets sets into the case a bit.
At this point a bullet will just set down into the case. It will set straight in the case.
Now if you seat the bullet it will seat straight. If the end of the case were it is expanded to just over bullet diameter is to large to allow the cartridge to chamber, you can adjust your seating/crimp die to crimp this edge in enough to allow the cartridge to fit the chamber.
On revolver rounds you can adjust the seat crimp to crimp this edge into the crimp groove of the bullet.
You can also push the case up to C, were the end of the case gets a flare. This is for Boolits that are cast to a lager size.
If you want you can get or make your own to better fit larger cast boolits.
I believe these are about the best way to expand for cast boolits.
Some one asked why their 7.62x54 dies came with two expanders. Most of the Russian built rifles had a bore size of about .300x.310 bore and land size, some went a bit bigger than this.
When the Russians fought with Sweden The Swedes captured a lot of the Russian Rifles. The Swedes rebarreled these rifles with a tighter bore, about .300x.308 bore and lands. So most die makers know this and supply two different expanders, one for the smaller bore size and one for the larger.
Leo

44magLeo
01-30-2019, 02:40 PM
I mentioned that I thought the M expander is great for cast boolits. The only thing I can think of to improve the loads would be to use a neck sizing die with inserts so you can neck size to have the case neck be the right size for your cast boolit or just under that size then use the M die to add the slightly over size section.
This neck sizing will extend case life and the M die will ensure straight seating.
Leo