Annealing During Case Forming

[Pawnee Bill]

I will be making some 6mm Remington brass by resizing Norma 257 Roberts +P brass. When, during the process of resizing through fireforming should I anneal the cases.

 

[JLT]

Annealing before running them into the 6mm die will help the forming process and lessen the chances of wrecking a case.

 

[JRS]

If the brass is new/unfired, you shouldn't have a problem. They are annealed from the factory.

 

[jepp2]

I will be making some 6mm Remington brass by resizing Norma 257 Roberts +P brass

When I am sizing down for 20 Practical, if, if, the brass is new, I don't anneal before sizing down. It was already annealed during manufacturing. But if the brass has been fired, I will anneal before sizing down. I also take the neck down in steps, not a single step. For my 0.020" reduction, I make 3 steps in neck reduction.

 

[NorCalMikie]

If the case gets "too soft" you may end up pushing the necks down into the case body. It's a trial and error thing so go slow but don't let it get to you. It's not rocket science.

 

[nmkid]

When I am sizing down for 20 Practical, if, if, the brass is new, I don't anneal before sizing down. It was already annealed during manufacturing. But if the brass has been fired, I will anneal before sizing down. I also take the neck down in steps, not a single step. For my 0.020" reduction, I make 3 steps in neck reduction.

Exactly!!

 

[ireload2]

You are over thinking this.
You are barely sizing down the cases one step of .014".
So size down to fit your chamber. Then shoot a normal load.

Then anneal before the second loading.

Or sell your new unaltered .257 brass for about a $1.00 each and buy new 6mm Rem brass.

 

[Brians356]

I tested forming 6mm Rem from 7x57mm with a 257 Roberts FL die followed by a 6mm Rem FL die. You can expect neck walls to thicken by about .002" with a donut at the base of the neck. FWIW Ken Howell stipulated using "form, trim, and ream dies" when starting from 257 Roberts (not 7x57mm).
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[ireload2]

Howell might have advocated that in print. In the real world if you do not have those dies you just skip them and form with the best alternative dies that you can come up with or afford. Most folks will avoid reaming since it does not ensure concentricity of the neck ID to the neck OD. Competition for obsolete and limited production forming dies is pretty high on ebay so you should be prepared to spend a lot of money or troll for several years to find a set of forming dies at a decent "buy it now" price.
Anyone that has formed 25-06 brass from .30-06 with only a .25-06 FL die knows that you sometimes can get by with less elaborate dies.
When I get new FL or trim die I will normally take a longer case and form it to determine how long the die is from the head to the datum diameter. Those cases are usually .30-06 or .270. I store the formed case with the dies. It is fairly easy to step a 30-06 case down to a .257 and a 6mm. Annealing right off the bat is not required.

New Remington factory 6mm brass has a natural taper to the neck wall thickness. There is several thousandths taper per side which can be enough to defeat the use of a Lee collet neck die. If you are fussy about necks and dough nuts and such even Remington factory brass will not make you happy without turning it.
I have a case forming set for the .250 Savage that will pretty much form any smaller case from a 30-06. There are 2 intermediate forming dies, a .250 Savage trim die, a .256 reamer and a .250 Savage reamer die. To make to the .250 Savage you FL size it after reaming. To go to .22-250 use a .22-250 FL die after reaming. Since you can eventually find most cases I much prefer to buy brass in the right configuration. When the brass is totally obsolete the .250 Savage forming die set can be used to make any number of obsolete cases including brass with a smaller head diameter such as the 6.5X53R Dutch Mannlicher or the 6.5mm Japanese Arisaka. The Dutch brass is not really available except at 1 or 2 custom sources. Existing sources of 6.5 Japanese brass are underside at the head. So there are often some very good reasons to use forming dies.

I tested forming 6mm Rem from 7x57mm with a 257 Roberts FL die followed by a 6mm Rem FL die. You can expect neck walls to thicken by about .002" with a donut at the base of the neck. FWIW Ken Howell stipulated using "form, trim, and ream dies" when starting from 257 Roberts (not 7x57mm).
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[fguffey]

It would help to understand what the OP is doing. He is not forming the cases, he is necking the down from 257 to .243 meaning he is necking the case down. Glossary of terms: When I neck a case down, load and then fire it I eject a once fired case. I understand the lofty term for a once fired case is a fire formed case. I form first and then fire.

When forming cases my favorite case to use the new, unfired case. To avoid confusing anyone I try to make it very clear work hardened fired cases is not a good choice when forming.

When forming I measure the length of the chamber from the shoulder to the bolt face, meaning if I need to off set the length of the chamber with the length of the case there is no better time to take care of that when forming, again, the OP is not forming cases, he is necking cases down.

F. Guffey

 

[Brians356]

Howell might have advocated that in print. In the real world if you do not have those dies you just skip them and form with the best alternative dies that you can come up with or afford.

That's why I prefaced the Ken Howell aside with "FWIW". And I had just previously stated that I personally formed 6mm Rem successfully from 7x57 using only 257 Roberts and 6mm Rem FL dies. Preaching to the choir?

New Remington factory 6mm brass has a natural taper to the neck wall thickness. There is several thousandths taper per side which can be enough to defeat the use of a Lee collet neck die. If you are fussy about necks and dough nuts and such even Remington factory brass will not make you happy without turning it.

I don't believe I have ever possessed a raw factory case (and I have a fair collection) which doesn't have tapered neck walls. That's perfectly normal AFAIK for every brand and model of case. I'd be interested to know which factory case is offered today with necks pre-turned, providing zero-taper neck walls.
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[Brians356]

Most folks will avoid reaming since it does not ensure concentricity of the neck ID to the neck OD.

I disagree. A proper tight-fitting ream die and a quality reamer are better for creating OD/ID concentricity (and removing a donut) than outside neck turning. But as you point out it is very expensive and a ream die may not even exist for a particular cartridge.
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