Neck turning on fired brass?

[jmcgowe]

I understand that it is recommended that neck turning be done with new brass. Is there any downside to doing it on once or twice fired brass? Thank you.

 

[tenring]

No, but first, size the necks as you would normally, then open them up with an expander before neck turning. Set the depth guage to turn just barely into the neck-shoulder junction

 

[Shynloco]

No, but first, size the necks as you would normally, then open them up with an expander before neck turning. Set the depth guage to turn just barely into the neck-shoulder junction

Agreed! Keep in mind the purpose of "Neck Turning" is to size the necks of your brass to a certain and uniform thickness and/or to clean up any high spots your brass may have. Neck thickness also can assist you in achieving neck tension for better control of your bullet's release. So just be careful in not cutting too much off if you are getting good accuracy with the present Neck Thickness of your brass.

Alex

 

[jmcgowe]

Agreed! Keep in mind the purpose of "Neck Turning" is to size the necks of your brass to a certain and uniform thickness and/or to clean up any high spots your brass may have. Neck thickness also can assist you in achieving neck tension for better control of your bullet's release. So just be careful in not cutting too much off if you are getting good accuracy with the present Neck Thickness of your brass.

Alex

Many thanks for quick and helpful replies.

John

 

[XTR]

Be careful cutting into the shoulders. I was at a match last yr with an Open shooter who was shooting the necks off of a lot of his brass, probably due to letting the cutter get into the shoulder too far.

 

[Shynloco]

Be careful cutting into the shoulders. I was at a match last yr with an Open shooter who was shooting the necks off of a lot of his brass, probably due to letting the cutter get into the shoulder too far.

Excellent point! Don't get crazy. A small/slight but visual circle in the shoulder is plenty as you DO NOT want to create a weakness in the brass head.

Alex

 

[Brians356]

I have recently been convinced that it's better to turn necks after firing once. That way the cases will be more uniform in the shoulder than virgin cases. (I suppose an exception might be made for so-called premium stuff like Lapua or <ahem!> Nosler.)

However one might not be able to fire prior to the first turning w/ a tight-neck chamber, where the OEM neck walls might be too thick to safely load and shoot, or if cases were custom formed from larger ones, resulting in thicker necks (e.g. 6mm Rem from 7x57). Someone suggested to me taking a skim pass just short of the shoulder, just to make the necks safe to load and fire, then do the final turning pass into the shoulder slightly, and down to the desired neck wall thickness. (Or, fireform the cases "bulletless" before turning necks.)
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[mikecr]

Lapua & Norma come new ready for the expanding/turning/loading.

If turning fired necks you can run into a difficult situation -> proper turning mandrel fit.
You fire the brass, necks expand to chamber & springback, not good for turning. You FL size those necks & they spring back to something not matching your turning mandrel or your new necks or your expander system design(for new necks). Could be anything at that point & folks do run into issues here. After all, a FL sizer is not adjustable in downsizing of necks, and your chamber neck clearance(once fired) will affect results from it. If everything lines up it'll work. How lucky are you?

There are situations where a wildcat cartridge needs some fire forming before turning. This can be accomplished even in a tight neck chamber with COW fire forming. But the type of loader going here is likely determined enough to git-r-done.

 

[Brians356]

If turning fired necks you can run into a difficult situation -> proper turning mandrel fit.
You fire the brass, necks expand to chamber & springback, not good for turning. You FL size those necks & they spring back to something not matching your turning mandrel or your new necks or your expander system design(for new necks). Could be anything at that point & folks do run into issues here. After all, a FL sizer is not adjustable in downsizing of necks, and your chamber neck clearance(once fired) will affect results from it. If everything lines up it'll work.

No luck required: Fireform. FL resize. Expand. Neck turn.

Do you slide new unfired cases onto your neck turner mandrel and turn them, just as you find them?
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[4xforfun]

I have turned many, many hundreds of pieces AFTER they have been fired a bunch of times. Just last week I turned some 6-47L brass that had 8 firings on them. I have done lots of 300 wsm brass after they had been fired 4- 6 times. Actually prefer it......all of the shoulders are in EXACTLY the same place!!!!!

Now, I am talking about custom chambers. The 6-47L is a .272 no turn that was sitting at .271xx loaded and the 300 WSM cases are a tight neck (.334) that I had turned when I was in My "1/2 thou per side clearance" stage of my life.....which is to close for comfort for me anymore!!

 

[Brians356]

And WRT necks: Virgin brass, even after expanding on a good mandrel, seems to not be uniform. By firing them the neck walls, like the shoulders, get ironed out against the chamber walls, and measure more uniform with a ball mic. They will still have one side of the neck thicker then the opposite (before turning) but the transition is smooth, while the virgin necks seems to have lumps in them revealed by the mic readings jumping up and down some as you progress around the neck.
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[DRNewcomb]

I find that after several loadings, the necks tend to thicken a bit on one side. Subsequent neck turnings tend to shave a bit off one side but not the other. Not sure if that's normal or diagnostic of some problem.

 

[LRCampos]

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I usually do neck turning after first fired the case. This way I can get the brass (more) consistent after passing it on my FL die, than having the brass new from factory and unknown factory sizing.


LRCampos.

 

[hoz53]

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I usually do neck turning after first fired the case. This way I can get the brass (more) consistent after passing it on my FL die, than having the brass new from factory and unknown factory sizing.


LRCampos.

A question to all you guys---so I take it you should use a FL die and not a bushing die if you're going to neck turn?

 

[spclark]

...so I take it you should use a FL die and not a bushing die if you're going to neck turn?

Right.

Bushing dies can leave an unsized portion of the neck just above the shoulder. Using a FL die eliminates that possibility, follows my practice.

Even if such a die sizes necks more than you'd otherwise feel necessary, annealing fired & cleaned cases before sizing helps maintain consistent brass condition.

After carefully matching an expander mandrel to my neck-turning mandrel's diameter, necks are expanded then turned, then trimmed to length.

Another benefit is that FL sized necks that are then mandrel-sized will have any thickening above the shoulder - that 'donut' you hear about - pushed to the outside where neck-turning will shave most of it (edited after reading post in reply!) away.

 

[hoz53]

Right.

Bushing dies can leave an unsized portion of the neck just above the shoulder. Using a FL die eliminates that possibility, follows my practice.

Even if such a die sizes necks more than you'd otherwise feel necessary, annealing fired & cleaned cases before sizing helps maintain consistent brass condition.

After carefully matching an expander mandrel to my neck-turning mandrel's diameter, necks are expanded then turned, then trimmed to length.

Another benefit is that FL sized necks that are then mandrel-sized will have any thickening above the shoulder - that 'donut' you hear about - pushed to the outside where neck-turning will shave it away.

That's what I thought. Thanks

 

[Brians356]

Another benefit is that FL sized necks that are then mandrel-sized will have any thickening above the shoulder - that 'donut' you hear about - pushed to the outside where neck-turning will shave it away.

Not completely. There is considerable spring-back where the donut is, abetted by the "buttress" of the nearby shoulder. So in practice I find there will still be some donut remaining, but it should be lessened considerably. Probably annealing just before expanding might reduce the spring-back and remaining donut.

Brass spring-back explains the raison d'etre of neck reamer dies. In such a die, the outside of the neck is held tightly captive, allowing the guided reamer to remove virtually 100% of the donut.
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