M Type dies Redding? RCBS?
- Thread starter Billglass
- Start date
If you look in the Redding catalog, all of their pistol expander die drawings appear to produce the M type step, but they are drawings and not photos. Give them a call to confirm. I have a lot of their rifle dies, but none for pistol.
I believe Hornady dies also use the step. But again, that's from illustrations. I don't have a set to say first hand.
You can also buy the Lyman Multi-expander die. This die is a powder-through die so you can charge the case with the expander still in it if you have a progressive press and are short an extra expander station. The Multi-expander comes with interchangeable expanding inserts that cover 32, 9mm, 38/357, 10mm/40 S&W, 41, 44, & 45 calibers. I have one, and it functions just fine. The inserts are machined more roughly than Redding gear is, but they work.
I believe Hornady dies also use the step. But again, that's from illustrations. I don't have a set to say first hand.
You can also buy the Lyman Multi-expander die. This die is a powder-through die so you can charge the case with the expander still in it if you have a progressive press and are short an extra expander station. The Multi-expander comes with interchangeable expanding inserts that cover 32, 9mm, 38/357, 10mm/40 S&W, 41, 44, & 45 calibers. I have one, and it functions just fine. The inserts are machined more roughly than Redding gear is, but they work.
The Lyman sketch from Lyman’s Instructions (Attached) shows that step 2 seems to have more of vertical sides rather than a flair.
https://www.lymanproducts.com/media/catalog/product/a/l/all_pistol_neck_expanding_m_die.pdf
Hornady’s expander die has an elliptical cone, definitely not stepped like the Lyman M Die but the seating die uses a floating bullet alignment sleeve and floating steel seating stem to keep everything lined up
I’m not sure about the Redding expander – it appears to have a taper at the bottom, straight sides and then a taper at the top. I called them, but no one answered…they’re getting the snow storm – so maybe they all stayed home like I did. I left a question at their “contact us” section – so I hope to hear from them later in the week.
For now I'm only considering the stepped die for 357 - which I load on a single stage and batch processing - so i can have as many steps in my process as I need or want.
I really like Redding's Profile Crimp die and their other equipment.
So, I'd like to get Redding
https://www.lymanproducts.com/media/catalog/product/a/l/all_pistol_neck_expanding_m_die.pdf
Hornady’s expander die has an elliptical cone, definitely not stepped like the Lyman M Die but the seating die uses a floating bullet alignment sleeve and floating steel seating stem to keep everything lined up
I’m not sure about the Redding expander – it appears to have a taper at the bottom, straight sides and then a taper at the top. I called them, but no one answered…they’re getting the snow storm – so maybe they all stayed home like I did. I left a question at their “contact us” section – so I hope to hear from them later in the week.
For now I'm only considering the stepped die for 357 - which I load on a single stage and batch processing - so i can have as many steps in my process as I need or want.
I really like Redding's Profile Crimp die and their other equipment.
So, I'd like to get Redding
Attachments
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What happens with the Lyman is the part labeled 1 on that die drawing enters the case mouth freely and only expands the case enough to overcome excessive resizing of a pistol case, as happens with thicker case walls. The part labeled 2 puts the step in the case. Above that is an un-numbered wider part, and when you run into that with your case it produces a flare for lead bullets, which need a little extra expansion to be sure the brass doesn't shave them. You do not need the flare for jacketed bullets. Just step 2.
The drawings I saw in the Redding catalog appear to be the same, but, as I say, I don't have any Redding pistol dies to look at. The Hornady die ( also appears to me to do the same thing in photos.
It also helps that I know what I am looking for. In photos the slight change of expander thickness that forms the step can be very hard to see.
The drawings I saw in the Redding catalog appear to be the same, but, as I say, I don't have any Redding pistol dies to look at. The Hornady die ( also appears to me to do the same thing in photos.
It also helps that I know what I am looking for. In photos the slight change of expander thickness that forms the step can be very hard to see.
Powder-thru-expanders from both RCBS and Mr. Bullet Feeder (to replace Dillon's P.T. expanders) have the "M" die's feature.
They allow dropped pistol bullets from bullet feeders to "stick" vertically to withstand the sideways movement to the next station on a progressive, without resorting to excess flaring/expanding.
Lyman is the only source I know about who has the same feature for rifle cases too. Such makes loading lead much easier, I hear.
They allow dropped pistol bullets from bullet feeders to "stick" vertically to withstand the sideways movement to the next station on a progressive, without resorting to excess flaring/expanding.
Lyman is the only source I know about who has the same feature for rifle cases too. Such makes loading lead much easier, I hear.
Follow up with Redding
I asked REDDING if they SELL A 2 STEP EXPANDER DIE FOR 357 FIRST STEP FOR EXPANDING TO JUST UNDER BULLET DIAMETER FOR NECK TENSION AND 2ND STEP A LITTLE OVER BULLET DIAMETER TO SEAT BULLET IN CASE
SIMILAR TO LYMAN M TYPE DIES?
Redding responded
Our expander found in the expanding die does just what you asked (see attachment).
Let me know should you have any further questions.

Thank you for using Redding Reloading Equipment.
Have a nice day,
Scott Lawrence
Customer Service Supervisor
cssl@redding-reloading.com
www.redding-reloading.com
I've attached an image they sent along and below is an explanation of their expander.
Technical Tips
Expanding Pistol and Straight Wall Cases
Lately, we have had several questions about flaring the case mouth of straight wall and pistol cases.
Generally, after resizing the case, you will run it onto the expander plug until you just barely flare the mouth of the case. There is no hard and fast rule, but a .010 increase in diameter is a good place to begin. Then adjust the expander up or down until you have minimal flare while still allowing the bullet to start into the case easily. Also be aware that the amount of flare is affected by the trim length of your cases. A shorter case will have less flare while a longer case will have more.
The Redding expander plug has two working diameters and an angle to create the flare. The smallest diameter is slightly under SAAMI nominal bullet diameter to establish correct neck tension for bullet retention. The narrow band is slightly over nominal bullet diameter to create a "shelf" for the bullet to sit on and remain straight while seating. The arrow in the illustration shows the approximate location of the case mouth to create a good flare.
Pistol_Expander2.psd ¨
I was hoping Redding would have this die
I asked REDDING if they SELL A 2 STEP EXPANDER DIE FOR 357 FIRST STEP FOR EXPANDING TO JUST UNDER BULLET DIAMETER FOR NECK TENSION AND 2ND STEP A LITTLE OVER BULLET DIAMETER TO SEAT BULLET IN CASE
SIMILAR TO LYMAN M TYPE DIES?
Redding responded
Our expander found in the expanding die does just what you asked (see attachment).
Let me know should you have any further questions.

Thank you for using Redding Reloading Equipment.
Have a nice day,
Scott Lawrence
Customer Service Supervisor
cssl@redding-reloading.com
www.redding-reloading.com
I've attached an image they sent along and below is an explanation of their expander.
Technical Tips
Expanding Pistol and Straight Wall Cases
Lately, we have had several questions about flaring the case mouth of straight wall and pistol cases.
Generally, after resizing the case, you will run it onto the expander plug until you just barely flare the mouth of the case. There is no hard and fast rule, but a .010 increase in diameter is a good place to begin. Then adjust the expander up or down until you have minimal flare while still allowing the bullet to start into the case easily. Also be aware that the amount of flare is affected by the trim length of your cases. A shorter case will have less flare while a longer case will have more.
The Redding expander plug has two working diameters and an angle to create the flare. The smallest diameter is slightly under SAAMI nominal bullet diameter to establish correct neck tension for bullet retention. The narrow band is slightly over nominal bullet diameter to create a "shelf" for the bullet to sit on and remain straight while seating. The arrow in the illustration shows the approximate location of the case mouth to create a good flare.
Pistol_Expander2.psd ¨
I was hoping Redding would have this die
Attachments
Bill,
Hmm. Sounds suspciously like what I described.
GWS,
Not just for lead. Set the rifle M die up so it produces the step without going quite deep enough to produce a flare. Bullet seated into that step have consistently lower runout than those sitting in the cone of a chamfer. Can cut groups up to about an moa in some guns.
Hmm. Sounds suspciously like what I described.
GWS,
Not just for lead. Set the rifle M die up so it produces the step without going quite deep enough to produce a flare. Bullet seated into that step have consistently lower runout than those sitting in the cone of a chamfer. Can cut groups up to about an moa in some guns.
Unclenick
thanks for the help getting through my confusion. They are hiding their 2 step die!! among their regular dies!!
I didn't want to sound like I doubted you....I was just surprised that Redding didn't list and name their "M" type die as some kind of specialty die. They have all kind of other specialty dies. You were right....its seems they changed all of their expander dies.
thanks for the help getting through my confusion. They are hiding their 2 step die!! among their regular dies!!
I didn't want to sound like I doubted you....I was just surprised that Redding didn't list and name their "M" type die as some kind of specialty die. They have all kind of other specialty dies. You were right....its seems they changed all of their expander dies.
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Ahh! I wondered at the cause of the hesitation. No, there's no special name. It's now their standard expander profile. Same with Hornady. The patent on the Lyman M profile, which Lyman also uses universally, expired long ago. I think Lyman kept the special name because it was already identified in the marketplace with their product. The others just use the profile and don't bother to mention it as special. Lee and Dillon and RCBS don't use it. CH4D has what they call an M type expander plug, but they use letters to designate all their product lines and I think this M is their own designation, as the photos don't appear to be the same thing. You'd have to call and ask them.