Lyman M-Die Expanding Plug Part Numbers

If anyone knows of other plug P/Ns, by all means, do share the wealth. Contact me HERE
http://www.lymanproducts.com/lyman/d...eckExpDies.php - but no parts list
A Table Of Lyman "M" dies Norm Johnson formerly HERE
Lyman Die Instructions

NOE Lee-Lyman Hybrid M-Die Plugs for Lee Expander  Rifle HERE and Pistol HERE
"Expander plug 1st Step x 2nd Step - To use with Lee Universal Neck Expanding Die Turns it in to a true neck expander like a Lyman M-die.


Lyman M-Die Expander Stems (only sells plugs and stems together)
From Lyman 1-800-225-9626. $6.50 for each plug/stem combo. The plugs are only sold WITH the threaded holders and are $6.50 each. As for the M-die bodies, these are also only available by phone.

The Lyman Expander Plug Steps
The Neck-Expanding “M” die expands and flares case mouths to ease bullet seating. It is included in all three-die sets and may be purchased separately for most cartridges. Cast bullet reloaders should use this die to prevent “shaving” of bullet metal during the seating operation.

1) First step expands inside of case neck to just under bullet diameter for precise case neck tension in the finished reload. 2) Second step expands case mouth to bullet diameter or slightly over. Jacketed or
cast bullets start perfectly centered and properly aligned w/ axis of caseneck.
NOTE: By adjusting the neck expanding plug slightly deeper, Step 2 also provides a slight flaring of  case mouth for reloaders using cast bullets.

Side View

Figure 2 shows cutaway views of Neck-Expand dies with cartridge cases in position. This die is identified by the “NECK EXPAND” stamped between the knurled top and threaded shank of the die body. Note the two-step expanding plug in the die. The first step of this plug expands the neck to slightly under bullet diameter while the second step expands the first 1/16" of the neck to slightly over bullet diameter. This allows cast bullets to enter the case without shaving lead.

Adjusting the Neck-Expanding “M” Die: Remove the expanding plug stem from the die body. Loosen the set screw and die lock ring and back off the die lock ring for sufficient room to screw the die body into the press. Lower the press handle until the shellholder is at its highest point, then screw the die into the press until the die’s bottom edge made light contact with the shellholder. The die body is now adjusted. Turn down the lock ring and tighten its set screw.

Your expanding plug must now be adjusted to the proper depth. Start the expanding plug stem into the die body. Place an empty, sized cartridge
case in the shellholder and lower the press handle until the shellholder is again at its highest point. Turn in the expander plug stem until you feel the expander plug contact the case mouth. This means the first (and narrower) stage of the plug is entering the case mouth.

Lift and lower the press handle slightly while continuing to adjust the expanding plug stem until it flares the case mouth. The case mouth should be flared enough to allow your bullet to easily enter the mouth without shaving lead or jacket material. With the Neck-Expanding Die adjusted, secure the expander plug lock nut.


Lyman M die bodies M1 on left, M2 on right. The threaded portion of the dies are the same



M1 - OAL 2.872, knurl length .931 (C.F.Plinker - 2-7/8" long for cases 1.3" to 2.25")
M2 - OAL 3.347, knurl length 1.380 (CFP - 3.34" long for cases @ 2.0" to 2.95" long)

CFP - Either body works from 2 to 2.25 inches . Example: .308, 30-30, and 303 Savage.
















Lyman M die stems, threaded portion is same


Long stem - 2.627 OAL (extension .858") Pistol and revolver cartridges
Short stem - 1.754 OAL Rifle cartridges.
















Lyman M die Rifle expanding plugs
Plug 1st 2nd Bullet dia
22R .222 .225 .222 .226 P/N 7129055 (22R Short)
24R .242 .246 .243 .244
25R .255 .259 .256 .257
26R .262 .266 .263 .265 P/N 7129059
27R .276 .280 .277 .279
28R .282 .286 .283 .285
30R .307 .311 .308 .310 P/N 7129101
31R .310 .314 .311 .313 P/N 7129064 (31R Short)
31AR .318 .322 .319 .321
32R .320 .324 .321 .323 P/N 7129065
33R .337 .341 .338 .340
35R .357 .361 .358 .360
37R .374 .378 .375 .377
41R .407 .412 .408 .411 (40-65, thanx to EDG)
43R unknown, (reported by Guesser)
45R .455 .459 .456 .458 P/N 7129078
50R (50-70)

Lyman M die Pistol expanding plugs
Plug 1st 2nd Bullet dias
25AP .249 .253 .251 --
30P .307 .311 .308 .310
32AP .310 .314 .311 .313
32P .313 .317 .314 .316
38AP .353 .357 .354 .356 P/N 7129050
38P .356 .360 .357 .359
10MM .398 .402 .399 .401
10MM .408 .412 .409 .411 (typo???)
41P (41 Rem Mag) (useable w/40-65)
44MP .427 .431 .428 .430
45AP .450 .454 .451 .453 P/N 7129051
45P .453 .457 .454 .456

50R Plug Dimensions
EDG wrote:
"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 - 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. "