Necking up and down?


Well-known member
Dec 20, 2000
I know how to do informal necking...;), but was wondering about doing this with cartridges. For the sake of discussion, lets say I want to build 22-6mm Rem. To neck down could I just order a set of neck sizing dies to get this right? My reason for asking is that I see neck sizing dies for specific cartridges. Could one use a .223 neck die for this or something like the Redding or Hornady neck dies? I noticed that Hornadies neck dies are list by cartridges just for calibers, .224, .243 etc..

Another example, if I wanted to build a 6X47 would I neck up the .222 Mag case by using a 6mm neck sizing die? I'm a little lost on how this is done and would appreciate any and all advice/information.

Calif. Hunter

Active member
Dec 13, 2000
La Palma, CA, USA
I've never really done this, so I could be totally wrong. I don't think that you can use a neck sizing die to neck down or up since it might (probably would?) affect the shoulder or possibly crumple the case without the support of the sidewalls of a regular sizing die. I could be wrong about this...

Where's Danr?


Active member
Dec 18, 2000
Mesa, AZ
1 Pointer, It depends on which way you are going and how much change you are going to make. Sometimes, if you are necking a cartridge down, you wind up with so much material in the neck that you have to ream the ID to size. Another thing you have to think about is moving the shoulder. If you move the shoulder too far back, you may need to have special sizing dies for the first resizing after fire forming.

If you neck a cartidge up, then you have to consider material thinning and make sure that you have enough material left to hold the pressure.

Case in point... I shoot an 8mm Wildcat called a 8X62 Durham Magnum. I make cases for 300 H&H brass. I also shorten the case by a little more than .125".

1. So first I have to run them through a necking die that pushes the shoulder back.
2. Then I run them through a trim die that lets me trim them to length.
3. Then the cases come out and get chamfered around the case mouth.
4. Then they go back in a reaming die for neck reaming. This removes enough material from the inside of the neck so the bullet fits in the chamber.
5. Then the cases get fire formed and the shoulder gets pushed forward.
6. After cleaning, they go back in the ream die and get the extra material removed from the neck that was pushed up there by fire forming.

Then the cases are done. This round pushes a 220 grain 8mm slug about 3100 fps and shoots under 3/4 inch groups at 300 yards. (When I am in really good shape.) That's why I continue to go through that. The rifle is awsome....

So it writes simple but is really a lot of work. If you want to build a 6X47, you can either neck up 222 mag or run 223 rem through a 6X47 size die. Which ever way you want to go, be sure the lube the inside of the neck and only use really clean cases. Clean helps make everything work better.


<FONT COLOR="#800080" SIZE="1">[ 04-02-2002 06:38: Message edited by: danr55 ]</font>

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