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Neck donut, some advices for...

RTTY

RTTY

Sergeant of the Hide
Full Member
Minuteman
Sep 5, 2023
221
60
Italy
#1
... prevent or solve the issue?

I've my fired cases (6,5x47 Lapua) with donuts.

I load with Lapua Scenar 139gn and don't engage the donuts with the bearing surface.

So have some advices, trick, for prevento or solve the donuts?

Thanks, Camillo
 
#3
Good video though one note, K&M neck turning tools cut out the donut both from the outside and inside so may be worth trying - your experiences may vary.
 
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#4
One of my K&M neck turning pilots has the carbide donut cutter on it - I think it's 6.5mm, from back in the before times when I had to 'make' 6.5-08 brass from either Winchester .308 or Lapua .243 brass and there was a fair bit of neck turning involved either way. Depending on how you did it (.243 to 6.5), donuts formed right from the get-go as the thicker shoulder material was now part of the new 'neck', at least at the base. I remember that K&M cutter left a pretty ugly interior finish - definitely needed some polishing with #0000 steel wool on a brush and a drill to clean up the surfaces after that thing got done. Then again, that was *very* early in my 'precision' reloading career, so it's entirely possible I wasn't doing it 'right' :rolleyes:

Not sure how the surface finish left by that compares with say, the LE Wilson inside neck reamer. 🤷‍♂️
 
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#5
RTTY said:
... prevent or solve the issue?

I've my fired cases (6,5x47 Lapua) with donuts.

I load with Lapua Scenar 139gn and don't engage the donuts with the bearing surface.

So have some advices, trick, for prevento or solve the donuts?

Thanks, Camillo
Click to expand...
Using an expander mandrel after sizing (using no spindle with expander button) tends to move any donut to the outside. . . especially well when annealing the brass.

Turning the necks where the cutter cuts a little into the shoulder, when done correctly, will prevent growth of the donut.

If one is using a bushing sizing die, the bushing doesn't size all the way down leaving the interior ID at the neck-shoulder junction large enough where donut growth doesn't come into play.

Neck sizing with a collet die can squeeze away the donut, moving that brass material into the neck.

The donut can be cut away with a good reamer run through the neck (like the one K&M has).

Choose your poison. ;)
 
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#7
simonp said:
Good video though one note, K&M neck turning tools cut out the donut both from the outside and inside so may be worth trying - your experiences may vary.
Click to expand...
Yes the K&M are on my playlist...
But I ready se me impression of users that the internal reamers don't leave a good finishing internal surface, @memilanuk confirm the "issue"...
 
#8
straightshooter1 said:
Using an expander mandrel after sizing (using no spindle with expander button) tends to move any donut to the outside. . . especially well when annealing the brass.
Click to expand...
Yes I can use and expander for the tension of the neck.
Yes I anneal my brass after a single firing.

straightshooter1 said:
Turning the necks where the cutter cuts a little into the shoulder, when done correctly, will prevent growth of the donut.
Click to expand...
What angle of cutter I can choice for my 6,5x47 Lapua cases?

straightshooter1 said:
If one is using a bushing sizing die, the bushing doesn't size all the way down leaving the interior ID at the neck-shoulder junction large enough where donut growth doesn't come into play.
Click to expand...
I have 2 bushing die from Forster, One for the neck and one full, I think that I made the worst choice of my reloader life...

I think that the best sizing die are the old scool non bushing full length...

straightshooter1 said:
Neck sizing with a collet die can squeeze away the donut, moving that brass material into the neck.
Click to expand...
You speak for collet sizing by Lee?
I don't think it exists for the 6.5x47 Lapua.
But ok!

straightshooter1 said:
The donut can be cut away with a good reamer run through the neck (like the one K&M has).

Choose your poison. ;)
Click to expand...
Finishing need some extra work...

Thanks!
 
#9
RTTY said:
Yes I can use and expander for the tension of the neck.
Yes I anneal my brass after a single firing.
Click to expand...
This is my go to method. I use a Forster FL sizing die that's been reamed so that it only reduces the neck .002 - .003 below my target OD, then use an expander mandrel to set my neck tension. This give me the best neck TIR (they're neck turned after fire forming), and. . . moves any donut away.

FYI: I've tested the ID with pin gauges before sizing to feel the donut and see how thick it is and afterwards to see if the donut is still there.

RTTY said:
What angle of cutter I can choice for my 6,5x47 Lapua cases?
Click to expand...
A 28° works nicely if you case neck is 30°.


RTTY said:
I have 2 bushing die from Forster, One for the neck and one full, I think that I made the worst choice of my reloader life...
Click to expand...
I'm just not a fan of bushing dies. Apparently, I have the same two Forster dies and I only use the neck bushing bump die to bump necks whenever I neck size with a collet die.

RTTY said:
I think that the best sizing die are the old scool non bushing full length...
Click to expand...
As mentioned, that's my preference too.

RTTY said:
You speak for collet sizing by Lee?
I don't think it exists for the 6.5x47 Lapua.
But ok!
Click to expand...
I think one would have to have Lee do a custom job for that cartridge. And I think there are a couple of other places, more expensive, that can do a custom collet sizing die.

RTTY said:
Finishing need some extra work...

Thanks!
Click to expand...
I've got a K&M reamer that I got for a test and it did ok. I didn't notice any unusual marks on bullets that I pulled to inspect. I just like the method I've settled on. :giggle:
 
#10
JR1200W3 said:
Best course of action is to prevent it. In your particular case you could have prevented it by paying what Lapua wanted for 6.5x47 brass.
Click to expand...
Can you explain me better please?


JR1200W3 said:
Making Franken brass results in artifacts in the brass like donuts. And now you have to buy tools to try to remedy the artifacts off-setting any real savings from making the Franken brass.
Click to expand...
What are Franken?
Brand Lapua?
Origin of the brand?
Explain please?

JR1200W3 said:
The K&m tool is probably the best solution for what you have going on. Wilson also makes an inside neck reamer that will cut out donuts but it requires you to have their trimmer.
Click to expand...
Yes Wilson requiren the brand trimmer.

Thanks
 
#11
straightshooter1 said:
This is my go to method. I use a Forster FL sizing die that's been reamed so that it only reduces the neck .002 - .003 below my target OD, then use an expander mandrel to set my neck tension. This give me the best neck TIR (they're neck turned after fire forming), and. . . moves any donut away.

FYI: I've tested the ID with pin gauges before sizing to feel the donut and see how thick it is and afterwards to see if the donut is still there.
Click to expand...
Hooned FL die, ok!

straightshooter1 said:
A 28° works nicely if you case neck is 30°.
Click to expand...
Perfect!


straightshooter1 said:
I'm just not a fan of bushing dies. Apparently, I have the same two Forster dies and I only use the neck bushing bump die to bump necks whenever I neck size with a collet die.


As mentioned, that's my preference too.
Click to expand...
Ok!

straightshooter1 said:
I think one would have to have Lee do a custom job for that cartridge. And I think there are a couple of other places, more expensive, that can do a custom collet sizing die.
Click to expand...
Other brands?

straightshooter1 said:
I've got a K&M reamer that I got for a test and it did ok. I didn't notice any unusual marks on bullets that I pulled to inspect. I just like the method I've settled on. :giggle:
Click to expand...
Do you use with an electric drill or battery screwdriver?

Thanks
 
#12
Couple of points first.
Mandrels never remove doughnuts, pure bullshit.
In my testing I have found the cases that have been resized using a expander ball pulled up through the neck
were less likley to create doughnuts vs pushing a mandrel down into the case. I no longer use mandrels because of this.


Cutting out doughnuts is a pain but there is a way to do it with very good results.

FL resize case (using 6.5 mm)

Push a .264 mandrel (bullet diameter) into the case neck just deep enough into the neck so it stops expanding the
neck just before it contacts the doughnut.

Using a doughnut cutter now will cut out the doughnut without cutting the inside of the neck
because the neck is .001 larger than the cutter.

Resize the case you should be good to go minus the doughnut.
 
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#13
whatsupdoc said:
Couple of points first.
Mandrels never remove doughnuts, pure bullshit.
Click to expand...
You're right, they don't actually "remove" donuts, but the mandrels do essentially move them out of the way, like moving the material to the outside; more so if the cases are annealed.

After annealing (as I do after every firing), I've taken pin gauges to measure the amount of "neck tension" and to see what the ID's of the donuts actually are. I've had as much as .002 difference between the ID of the donut opening and the rest of the case neck. After running my mandrel through the necks then the pin gauges to see any changes in the donut ID, there was no obstruction of the pin gauge all the way through for the "neck tension" I was setting. One of the reasons I bought some pin gauges was to find out definitively the size of the donuts before and after various sizing methods.

For necks that haven't been annealed, particularly those that have never been done after several firings, little or no movement of the donut by running a mandrel through the neck is expected due to the amount of springback.
 
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#15
JR1200W3 said:
Best course of action is to prevent it. In your particular case you could have prevented it by paying what Lapua wanted for 6.5x47 brass.
Click to expand...
RTTY said:
I've my fired cases (6,5x47 Lapua) with donuts.
Click to expand...
1733169334860.png
 
#16
straightshooter1 said:
You're right, they don't actually "remove" donuts, but the mandrels do essentially move them out of the way, like moving the material to the outside; more so if the cases are annealed.

After annealing (as I do after every firing), I've taken pin gauges to measure the amount of "neck tension" and to see what the ID's of the donuts actually are. I've had as much as .002 difference between the ID of the donut opening and the rest of the case neck. After running my mandrel through the necks then the pin gauges to see any changes in the donut ID, there was no obstruction of the pin gauge all the way through for the "neck tension" I was setting. One of the reasons I bought some pin gauges was to find out definitively the size of the donuts before and after various sizing methods.

For necks that haven't been annealed, particularly those that have never been done after several firings, little or no movement of the donut by running a mandrel through the neck is expected due to the amount of springback.
Click to expand...
They never move them to the outside that is a farce.
 
#18
JR1200W3 said:
He made a thread a month ago about forming his own 6.5X47L brass bc Lapua brass is really expensive in his part of the world. Granted, I am making the assumption this is his homemade formed brass and not actual factory brass, but you don't really get donuts randomly in factory brass. You get them when forming brass because former shoulder material becomes neck or similar situations.

I think most of the people here aren't aware of the backstory. Now reread my post and think about forming 6.5x47L brass from 6.5 Creedmoor brass and see if what I said makes any sense.
Click to expand...

Yep, with that backstory it makes sense but the OP said it was Lapua cases. Who knows
 
#20
JR1200W3 said:
He made a thread a month ago about forming his own 6.5X47L brass bc Lapua brass is really expensive in his part of the world. Granted, I am making the assumption this is his homemade formed brass and not actual factory brass, but you don't really get donuts randomly in factory brass. You get them when forming brass because former shoulder material becomes neck or similar situations.

I think most of the people here aren't aware of the backstory. Now reread my post and think about forming 6.5x47L brass from 6.5 Creedmoor brass and see if what I said makes any sense.
Click to expand...

Hello, no the case with donuts are brand Lapua cases, 6,5x47 factory made.
 
#21
JR1200W3 said:
Then it's extremely strange that you are getting donuts from factory brass. What are you doing that's creating donuts in the necks? Or are you positive you have donuts in the necks? This doesn't just randomly occur.
Click to expand...
Hello, sorry for my bad english and for the mistake, the donuts was formed on the fired factory 6,5x47 Lapua, not brand new.
 
#22
Hello,
the donuts was formed with normal use, normal charges with 35 or 36gn of N150 behind Scenar 139gn. Forming done with Forster bushing neck die and redding body die.
 
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