7mm SAUM or 280 AI

[RH300UM]

A doughnut is a brass build up at the inside base of the neck which narrows the I.D. and can affect accuracy and even pressure.
It is usually caused by the body of the bullet extending below the neck.
When it occurs, you have to mandrel it out and/or turn or ream the neck.

I'd have to disagree on the doughnut Rich
I've been shooting a 7saum for awhile now and never seen this. On my 7th firing for this brass. Loaded other 7 saums also never seeing that issue with those either

 

[Alex Wheeler]

Any case can grow a donut, but if your not seating the bullet into it, it is not an issue. With a saum in a short action, many bullets will be seated that deep. But if you use a bushing die which doesnt size that part of the neck, and pay attention to how the bullets seat, donuts can be managed. A 168 vld in a wyatts box works well in a 7 saum. 180s will be into the donut. Theres a newer box wyatts came out with thats even longer and may be the fix for the longer bullets. Strictly comparing the cases, the saum is a better design and it has better brass available. Now if ADG ever makes us some 280 brass, that would level things out quite a bit! The Nosler 280ai brass is bad.

 

[L.Sherm]

Now if ADG ever makes us some 280 brass, that would level things out quite a bit! The Nosler 280ai brass is bad.

Alex I agree 100%

 

[elkaholic]

I dont own one but thats what others have told me and I have seen it on other cases which has the same affect. Thanks for the personal experience.
OP. if the bullet stops near the base of the neck when dropped into the case mouth before sizing, you likely have a doughnut. Also, when you seat a bullet in a sized case and you feel resistance at the bottom of the neck, you have a problem.

 

[Sinko]

I shoot a 270 with a 22" barrel and a 280 AI with a 24.5" barrel. The Ackley is pleasant to shoot but a different animal than the 270. I like mine, a lot and wouldn't hesitate to build another one.

 

[Bob Wright]

Any case can grow a donut, but if your not seating the bullet into it, it is not an issue. With a saum in a short action, many bullets will be seated that deep. But if you use a bushing die which doesnt size that part of the neck, and pay attention to how the bullets seat, donuts can be managed. A 168 vld in a wyatts box works well in a 7 saum. 180s will be into the donut. Theres a newer box wyatts came out with thats even longer and may be the fix for the longer bullets. Strictly comparing the cases, the saum is a better design and it has better brass available. Now if ADG ever makes us some 280 brass, that would level things out quite a bit! The Nosler 280ai brass is bad.

Yep, been fighting the donut with Nosler brass and had to order neck turning kit from K&M for another attempt at correcting it. Wild pressure issues.

 

[6.5-300 BEE]

"Carried Long Distances" was missed by most. Here is the answer. 6 pounds loaded.

Kills Moose in Norway but won't kill an Elk here ------ Laffin !