Brass donuts

I’m curious too. I’ve been loading a long time and never experience the donut that I’m aware of.

It's really not that complicated. When you keep resizing a case, where the material is being squeezed back to a smaller size, think of it like squeezing an hand full of soft clay. The brass acts like clay when under high pressure and has to go somewhere and that somewhere is the place of least resistance; the shoulder and neck where the brass is the thinnest. That brass movement tends to accumulate at the neck-shoulder junction due to the angle change in direction.

How someone handles this issue can vary, as mentioned:
***A bushing die doesn't size all the way down to the neck-shoulder junction, so the donut can stay hidden out of the way.

***Using a mandrel after using a non-bushing die to push donut towards the outside can work, though there is some springback depending on the hardness of the case (proper annealing minimizes the springback). I've use pin gauges to measure how much donut there is and found there can be as much as .003" of donut thickness. And using a mandrel after annealing, I found the donut was moved out of the way.

***Seating a bullet high enough so the bearing surface doesn't make contact with any donut is another way to handle the issue. And it's one of the things I do to be sure there's no contact with any donut that might be there, just in case there any springback after mandreling.

As a bullet is being seated, if its bearing surface engages the donut it might move the donut a little. But there's boing to be uneven pressure on the bearing surface where the donut is applying more pressure than the rest of the neck. It just tend to produce inconsistent and uneven "neck tension" (interference).

or just pretend they don't exist. That is my normal practice.

I actually do want to take a couple pieces over to buddies with pin gauges and see if there's anything there worth doing something about but in general my rifles shoot good enough for me so why worry about it.

Schw15 said:

What dies do you use? First time I've really ever delt with one.

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SAC, mostly
Whidden
Redding type s
Hornady
And I have a Lee die or two.

I mandrel after sizing. I seat longer than spec (if there is one) but always within “magazine length”. And I don’t know about “sizing all the way to the neck shoulder junction”. I just set the die up and use it. I’m content if my SD is less than 10 and my ES is around 4xSD after 20+rounds. Beyond that, I don’t know about donuts.

Taylorbok said:

or just pretend they don't exist. That is my normal practice.

I actually do want to take a couple pieces over to buddies with pin gauges and see if there's anything there worth doing something about but in general my rifles shoot good enough for me so why worry about it.

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It's that really all it comes down to . . . "my rifles shoot good enough for me"?

They must be a thing. Fclass guys use custom ground non-bushing dies for some reason.

straightshooter1 said:

It's that really all it comes down to . . . "my rifles shoot good enough for me"?

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Yes. For me anyways

I don't shoot F-class or BR so trying to squeeze every little bit of accuracy is fruitless.
a slightly smaller group size isn't likely to produce any more points/ hits on plate.
Plus at the point I'd be curious to whether or not it actually has a meaningful impact on accuracy.

OREGUN said:

They must be a thing. Fclass guys use custom ground non-bushing dies for some reason.

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I think they do that for concentricity between the case body and the neck.

The short range benchrest shooters do use a bushing die.

Does someone have an easy explanation between a doughnut and a clicker? If I understand this correctly, a donut is up on the neck and a clicker is down at the base by the rim?

7mm-08 Freak said:

Does someone have an easy explanation between a doughnut and a clicker? If I understand this correctly, a donut is up on the neck and a clicker is down at the base by the rim?

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Donut is where either 1) thicker shoulder material migrates up into the neck with repeated sizing firings 2) unsized portion of the neck via bushing die.

Clicker is where the base of the case doesn’t have sufficient clearance between the cartridge and chamber base. After firing its wedged in there and when the primary extraction engages you feel a click as it breaks the brass free of the chamber.
Scroll down to the clicker video