Thread: 243 Ackley. Project getting closer, experiences and advice welcomed

I'm inclined to think that it might just be a common misconception that shoulders are always thicker than necks. The cases I have recently sectioned all had shoulders at the same thickness as the necks.
I'm not sure either that having the shoulders at the same thickness as the necks – or turning them thinner again – is a guaranteed way to prevent donuts. It could be that the neck-shoulder junction is a natural point for the build-up of brass on firing irrespective of the thickness of material from which it is derived.

Originally Posted by Puffin

I'm inclined to think that it might just be a common misconception that shoulders are always thicker than necks. The cases I have recently sectioned all had shoulders at the same thickness as the necks.
I'm not sure either that having the shoulders at the same thickness as the necks – or turning them thinner again – is a guaranteed way to prevent donuts. It could be that the neck-shoulder junction is a natural point for the build-up of brass on firing irrespective of the thickness of material from which it is derived.

Thats interesting, what cartridge and brand? Iv encountered thicker shoulders when necking up, the thicker brass pushing to the outside that needed turning off and have assumed they were all the same.
Donuts are bit of a mystery all right , I think you are correct in the junction being a point of buildup. Iv found they mostly form on the first or second firing and that relieving that area alleviates the problem for the life of the case. I tried inside turning on my 280ai but wasn't as successful.