Inconsistent seating depth

[TheDerkster]

seems it would be moved to the outside when using expander ball. i wonder if h.s. was very close on resized round would it chamber tightly? when you find out whats going on here please let us know.

Im gonna call John Monday about jb welding the stem to the bullet for a custom fit and go from there.

 

[barefooter56]

I looked, yes. But would that donut actually appear on the inside when using an expander ball? The outside was turned after neck sizing with an expander.

I guess in my mind, it should be the same thickness all the way through except the junction which should have been sized with the ball. Although it's denting the bullet before it even hits that point

Donuts will only appear after firing especially on hot loads . That's why you go up on the shoulder a little bit . To give the brass a place to flow though. Don't think that donuts are a common thing. They aren't. But if you are running a hot load or don't go up on the shoulder it may be more common. If you are doing either check. Removing the donut isn't hard. In some cases you can use the expander mandrel to push it back out. If you want to cut it out. Get an L.E. Wilson neck reamer that is about .001 under the bullet diameter to nip out the donut. Only do this on unsized fired brass ! L.E.Wilson lists their neck reamers on their sight and will make custom sizes I believe. The nice thing is that you don't need to use the reamer with the Wilson trimmer. They come with a thumb wheel and you can just do your donut removal free style. Many Bench rest shooters I know do it that way.

 

[Mikecr]

Don't think that donuts are a common thing. They aren't.

Donuts are merely thicker brass (than the rest of the neck) near neck-shoulder junction.
Donuts exist with all new brass, as it's inherent to case manufacture that brass thickness tapers from webs to all the way to mouths. This, anyone can measure with a good ball micrometer.
What could be considered common is donut thickness not actually interfering with anything. And if you don't size donut area, or seat bullet bearing near, it's not a problem.

Donuts can & should be mitigated by mandrel neck expansion prior to bullet seating(pre-seating), and/or with standard outside neck turning(after mandrel expansion) of NEW brass.