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Rifles, Reloading, Optics, Equipment
Reloading
Let's talk about the "dreaded donut"
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<blockquote data-quote="Trickymissfit" data-source="post: 485639" data-attributes="member: 25383"><p>necking up brass properly should never leave a doughnut inside the neck, but I can see where it could happen when reducing the neck size. Some folks will say a 40 degree shoulder will cause it, but you'll see it in a 20 degree shoulder as well. It's brass flow, and brass looking for the path of least resistence. In this case it's the junction of the shoulder and neck. A poorly machined sizing die will also do similar things (or chamber). Some folks think it's caused by 40 degree shoulders, and others don't. I see no connection. But a 30 degree shoulder is easier to form (pressure wise) than a 40 or even a 35 degree shoulder. Yet I see the same doughnut in my generic 22-250 cases (28 degrees), but do think it's more pronounced with a 35 or 40 degree shoulder. It's not the shoulder itself, but where the brass flow stopped. But with my 6/250AI I still see the doughnut, but seems to go a couple firings more it needs to be cleaned out (guess this does prove that a 40 degree shoulder will hinder brass flow).</p><p> </p><p>Lately my case designs are reverting back to the 30 to 35 degree shoulders simply becase they're easier to form, and maybe a tad bit less case shrinkage on fore forming (I have no concrete data to prove this out so far). Also to help create a bit for confusion: I see zero doghnuts with my Weatherby cases!</p><p>gary</p></blockquote><p></p>
[QUOTE="Trickymissfit, post: 485639, member: 25383"] necking up brass properly should never leave a doughnut inside the neck, but I can see where it could happen when reducing the neck size. Some folks will say a 40 degree shoulder will cause it, but you'll see it in a 20 degree shoulder as well. It's brass flow, and brass looking for the path of least resistence. In this case it's the junction of the shoulder and neck. A poorly machined sizing die will also do similar things (or chamber). Some folks think it's caused by 40 degree shoulders, and others don't. I see no connection. But a 30 degree shoulder is easier to form (pressure wise) than a 40 or even a 35 degree shoulder. Yet I see the same doughnut in my generic 22-250 cases (28 degrees), but do think it's more pronounced with a 35 or 40 degree shoulder. It's not the shoulder itself, but where the brass flow stopped. But with my 6/250AI I still see the doughnut, but seems to go a couple firings more it needs to be cleaned out (guess this does prove that a 40 degree shoulder will hinder brass flow). Lately my case designs are reverting back to the 30 to 35 degree shoulders simply becase they're easier to form, and maybe a tad bit less case shrinkage on fore forming (I have no concrete data to prove this out so far). Also to help create a bit for confusion: I see zero doghnuts with my Weatherby cases! gary [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Reloading
Let's talk about the "dreaded donut"
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