Confusion about 9mm sizing dies

[Will Abrahams]

I have been loading 40SW and 38SC for several years, but am now getting setup to load 9mm for carry optics.  I have some questions regarding sizing 9mm as it has more taper than 40SW.                                                                                                                                       

Are dies with a carbide sizing ring essentially turning the most of the case into a straight walled case?  I don't see how it couldn't unless the carbide sizing part of the die was the same length as the case and tapered.  I imagine that it wouldn't really matter as the round would still chamber, but changing the contour of the case from the original spec just seems a little strange to me.                                                                              

RCBS has dual ring carbide dies that has a lower and upper carbide ring.  My understanding is the lower ring is slightly larger so the brass doesn't get worked as much.  This design seems like it would preserve more of the original taper. Anyone have any experience with this die for 9mm?  

Edited December 3, 2019 by Will Abrahams

[Sarge]

53 minutes ago, Will Abrahams said:

I have been loading 40SW and S8SC for several years, but am now getting setup to load 9mm for carry optics.  I have some questions regarding sizing 9mm as it has more taper than 40SW.                                                                                                                                        Are dies with a carbide sizing ring essentially turning the most of the case into a straight walled case?  I don't see how it couldn't unless the carbide sizing part of the die was the same length as the case and tapered.  I imagine that it wouldn't really matter as the round would still chamber, but changing the contour of the case from the original spec just seems a little strange to me.                                                                              RCBS has dual ring carbide dies that has a lower and upper carbide ring.  My understanding is the lower ring is slightly larger so the brass doesn't get worked as much.  This design seems like it would preserve more of the original taper. Anyone have any experience with this die for 9mm?  

Everything is tapered

[Will Abrahams]

46 minutes ago, Sarge said:

Everything is tapered

Agreed, however, 9mm has more taper than 40SW as stated in my post 

 

40SW looks like it has a thousandth taper where 9mm has 10 thousandths.  

If neither amount of taper matters when sizing, that's great, but I just trying to understand what single ring carbide sizing dies are doing dimensionally to 9mm cases that have more taper than 40SW.

 

From your response it seems like the difference is inconsequential and I should quit thinking about it, get the lee die and start loading 

 

Edited December 3, 2019 by Will Abrahams

[Sarge]

34 minutes ago, Will Abrahams said:

Agreed, however, 9mm has more taper than 40SW as stated in my post 

 

40SW looks like it has a thousandth taper where 9mm has 10 thousandths.  

If neither amount of taper matters when sizing, that's great, but I just trying to understand what single ring carbide sizing dies are doing dimensionally to 9mm cases that have more taper than 40SW.

 

From your response it seems like the difference is inconsequential and I should quit thinking about it, get the lee die and start loading 

 

Sorry. I meant everything about a 9mm die is tapered. Carbide ring etc

[Will Abrahams]

4 minutes ago, Sarge said:

Sorry. I meant everything about a 9mm die is tapered. Carbide ring etc

ah gotcha, that makes more sense now.   Thanks for clearing that up 

[Yondering]

20 hours ago, Will Abrahams said:

Agreed, however, 9mm has more taper than 40SW as stated in my post 

 

40SW looks like it has a thousandth taper where 9mm has 10 thousandths.  

If neither amount of taper matters when sizing, that's great, but I just trying to understand what single ring carbide sizing dies are doing dimensionally to 9mm cases that have more taper than 40SW.

 

From your response it seems like the difference is inconsequential and I should quit thinking about it, get the lee die and start loading 

 

 

The carbide ring in most 9mm dies is much longer than it is in straight wall cases like 40 and 45. The ring is long enough to have the taper section built in, and also a straight section where the bullet is seated. 

 

That longer contact area and taper is partly why a lot of guys like to lightly lube their 9mm brass before sizing, even with carbide dies. I've gone that direction myself after many years of loading 9mm dry, and it's a good improvement in the loading process, just makes it easier.