Forming Die and Full Length Resizing Die

[Lostinidaho]

I have a 6mm Lee Navy

CHD lists a forming die. What is the difference between a full length sizing die and forming die.

I use .220 swift cases. But they are 4mm short. Light to make longer cases.

I tried to call but the line rings buzy. At this point it is just an educational question.

Thanks in Advance

[vzerone]

Case Forming Dies are used to create brass cases for hard-to-find or expensive cartridges out of readily available brass. They change the case in small steps to eliminate excessive stress on the brass. After forming and trimming, the cases must be full length sized for final forming. These sets may consist of one trim die or a whole set containing up to three dies, expander ball, ream die and reamer depending on the case being formed.

[Bent Ramrod]

Forming dies are usually set up to minimize case loss. To do this, the forming is done in stages: shoulder set back, trimming, neck resizing, maybe neck reaming, etc. When you are done, there generally is the need for fire forming in your chamber, and there you need the full-length size die. And then the seating die to reload.

However, the shoulder doesn’t move to move much to change the .220 to 6mm Lee, and the neck expansion is pretty nominal. I’ve run a bunch of .220 Swift into C-H/4D 6mm Lee sizing dies and never lost a case. Little point in bothering with forming dies unless you are going to do some really violent operations on a different case.

I was always hoping the necks on the reformed .220 Swift’s would stretch on repeated reloading as 6mm Lees. But they haven’t grown a nanometer that I can see.

If you want to get hold of Dave, you have to call him early in the morning. His phone doesn’t even ring in the afternoon, let alone take messages. If there is a die operation that lengthens the case, he should know.