I shoot a .308 and a .260. Never seen or heard of an issue with .308. We know that the .260 is prone to donuts after 4-6 firings. I'm looking at getting into the 7mm game. 7SAUM or 7wsm or 7BAT ... But it's not nailed down. Anyone experience donuts with the 7s? If so what caliber and what brass?
Donuts? For you 7mm guys
- Thread starter Tangodown911
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Re: Donuts? For you 7mm guys
Donuts in the brass are prevalent when brass is formed from a smaller to a larger bullet. IE, it is oft. heard of when taking 243 brass up to 260's.
You can cut them out with a neck reamer easily.
Donuts in the brass are prevalent when brass is formed from a smaller to a larger bullet. IE, it is oft. heard of when taking 243 brass up to 260's.
You can cut them out with a neck reamer easily.
Re: Donuts? For you 7mm guys
Can't help with the OP's question.
Unless I'm mistaken, 'donuts' are fat rings that can form at the inside base of the neck where the neck transitions into the shoulder, essentially reducing the I.D. of the neck at that point and changing the neck's grab on the bullet. I don't have any personal experience with this problem, just read about it in one of Glen Zediker's books.
Can't help with the OP's question.
Unless I'm mistaken, 'donuts' are fat rings that can form at the inside base of the neck where the neck transitions into the shoulder, essentially reducing the I.D. of the neck at that point and changing the neck's grab on the bullet. I don't have any personal experience with this problem, just read about it in one of Glen Zediker's books.
Re: Donuts? For you 7mm guys
My last step is to run a inside neck mandrel. Does a couple of things. Gets rid of any possible donuts, centers from the inside. Gives me very consistent neck tension.
My last step is to run a inside neck mandrel. Does a couple of things. Gets rid of any possible donuts, centers from the inside. Gives me very consistent neck tension.
Re: Donuts? For you 7mm guys
Donuts occur when you neck up because you are making neck from shoulder metal, which for many brands of brass (i.e. Lapua) is thicker than neck metal.
This is how I formed .284 Win. brass from Lapua 6.5x284 brass:
<ul style="list-style-type: disc">[*]Lube inside of case necks[*]Neck up using a Redding full-length sizer with the optional tapered expander button[*]Trim, chamfer, and debur[*]Run cases through an expander mandrel.[*]Between the FL sizing die and the mandrel, the donut will be pushed to the outside of the neck[*]Neck turn the cases, making sure to just bite into the should to fully remove the donut. I just do a light cleanup turn.[*]It's obvious where the donut is; even if you only do a light cleanup turn, there is a continous ring of removed brass at the neck shoulder junction[*]Clean cases[/list]
Basically, I followed this guide to neck turn the cases, never having done it before:
http://riflemansjournal.blogspot.com/2009/12/reloading-neck-turning.html
You want the cutter of your neck turner to closely match the angle of the shoulder so that you can "bite" into the shoulder without removing too much material. I used a Sinclair NT-3000 with a 40 degree cutter (.284 family has 35 degree shoulder), though now you can get neck turners with cutters that precisely match almost any commonly used shoulder angle from 21st Century Shooting.
Here are some threads on accurateshooter.com about removing the donut, from the .284 Win. perspective (but generally applicable, technique-wise):
http://forum.accurateshooter.com/index.php?topic=3496407.0
http://forum.accurateshooter.com/index.php?topic=3756174.0
Note that you may have to revisit the issue in subsequent firings, as the brass flows/lengthens as you shoot it.
Donuts occur when you neck up because you are making neck from shoulder metal, which for many brands of brass (i.e. Lapua) is thicker than neck metal.
This is how I formed .284 Win. brass from Lapua 6.5x284 brass:
<ul style="list-style-type: disc">[*]Lube inside of case necks[*]Neck up using a Redding full-length sizer with the optional tapered expander button[*]Trim, chamfer, and debur[*]Run cases through an expander mandrel.[*]Between the FL sizing die and the mandrel, the donut will be pushed to the outside of the neck[*]Neck turn the cases, making sure to just bite into the should to fully remove the donut. I just do a light cleanup turn.[*]It's obvious where the donut is; even if you only do a light cleanup turn, there is a continous ring of removed brass at the neck shoulder junction[*]Clean cases[/list]
Basically, I followed this guide to neck turn the cases, never having done it before:
http://riflemansjournal.blogspot.com/2009/12/reloading-neck-turning.html
You want the cutter of your neck turner to closely match the angle of the shoulder so that you can "bite" into the shoulder without removing too much material. I used a Sinclair NT-3000 with a 40 degree cutter (.284 family has 35 degree shoulder), though now you can get neck turners with cutters that precisely match almost any commonly used shoulder angle from 21st Century Shooting.
Here are some threads on accurateshooter.com about removing the donut, from the .284 Win. perspective (but generally applicable, technique-wise):
http://forum.accurateshooter.com/index.php?topic=3496407.0
http://forum.accurateshooter.com/index.php?topic=3756174.0
Note that you may have to revisit the issue in subsequent firings, as the brass flows/lengthens as you shoot it.
Re: Donuts? For you 7mm guys
Interesting post, nhm.
I neck up Lapua 6.5x284 brass by lubing the inside of the case, running it through a 7mm mandrel, then through my FL sizing (bushing) die that has only a carbide expander ball in place.
That's it. No neck turning.
Interesting post, nhm.
I neck up Lapua 6.5x284 brass by lubing the inside of the case, running it through a 7mm mandrel, then through my FL sizing (bushing) die that has only a carbide expander ball in place.
That's it. No neck turning.
Re: Donuts? For you 7mm guys
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Graham</div><div class="ubbcode-body">Interesting post, nhm.
I neck up Lapua 6.5x284 brass by lubing the inside of the case, running it through a 7mm mandrel, then through my FL sizing (bushing) die that has only a carbide expander ball in place.
That's it. No neck turning. </div></div>
Because the chamber neck is of a constant diameter, when you fire that brass, the donut which you had pushed to the outside when you initially ran the mandrel down the neck gets pushed back inside (since the outside of the case neck obviously has to conform to the chamber neck on firing).
However, a donut is not always a problem:
Because a bushing die does not size the entire neck, the part where the donut lays may not be sized down to the point where it constricts the inside neck diameter (though with my Redding FL bushing die it would). Moreover, in your case, even if the bushing did size down the donut area, the expander ball probably pushes the donut back to the outside.
Also, if you load your rounds long enough, the bullet bearing surface (the shank) never goes near the donut, i.e. when seated, the bullet's shank/boat tail junction sits above the donut, so it has no adverse effect.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Graham</div><div class="ubbcode-body">Interesting post, nhm.
I neck up Lapua 6.5x284 brass by lubing the inside of the case, running it through a 7mm mandrel, then through my FL sizing (bushing) die that has only a carbide expander ball in place.
That's it. No neck turning. </div></div>
Because the chamber neck is of a constant diameter, when you fire that brass, the donut which you had pushed to the outside when you initially ran the mandrel down the neck gets pushed back inside (since the outside of the case neck obviously has to conform to the chamber neck on firing).
However, a donut is not always a problem:
Because a bushing die does not size the entire neck, the part where the donut lays may not be sized down to the point where it constricts the inside neck diameter (though with my Redding FL bushing die it would). Moreover, in your case, even if the bushing did size down the donut area, the expander ball probably pushes the donut back to the outside.
Also, if you load your rounds long enough, the bullet bearing surface (the shank) never goes near the donut, i.e. when seated, the bullet's shank/boat tail junction sits above the donut, so it has no adverse effect.
Re: Donuts? For you 7mm guys
I follow this exact procedure but still had an issue with doughnuts. After running 6.5x284 brass across my 7mm sinclair expanding mandrel, the doughnut creates a lot of resistance when neck turning with the .001 smaller turning mandrel. Apparently the doughnut had some "spring back" after expanding. My neck is too tight to work with even the minor doughnut created with this operation.
I follow this exact procedure but still had an issue with doughnuts. After running 6.5x284 brass across my 7mm sinclair expanding mandrel, the doughnut creates a lot of resistance when neck turning with the .001 smaller turning mandrel. Apparently the doughnut had some "spring back" after expanding. My neck is too tight to work with even the minor doughnut created with this operation.
Re: Donuts? For you 7mm guys
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Re: Donuts? For you 7mm guys
Thanks guys for providing good information on neck turning. I'm still unclear if your experiences or knowledge dictate that donuts are will inherently occur on ie. 7saum brass used in a 7saum chamber or 7wsm brass used in a 7wsm chamber. Just as we know .260rem will develop donuts. So are the 7MMs prone to donuts like the .260rem or not?
I am not talking about necking up brass to make another caliber. I fully understand that necking up instantly causes donuts... And thank you to the guys that did take the time to post that info. But I am more concerned with donuts appearing on the popular 7MM chamberings due to repeated firings like the ones I have already mentioned.
Thanks guys for providing good information on neck turning. I'm still unclear if your experiences or knowledge dictate that donuts are will inherently occur on ie. 7saum brass used in a 7saum chamber or 7wsm brass used in a 7wsm chamber. Just as we know .260rem will develop donuts. So are the 7MMs prone to donuts like the .260rem or not?
I am not talking about necking up brass to make another caliber. I fully understand that necking up instantly causes donuts... And thank you to the guys that did take the time to post that info. But I am more concerned with donuts appearing on the popular 7MM chamberings due to repeated firings like the ones I have already mentioned.
Re: Donuts? For you 7mm guys
I have a 7WSM and use only W-W 7 WSM brass. I have it all annealed and then just load and shoot. Never had any issue with donuts being created with it. mine is not a tight neck chamber though.
I am now using Lapua 260 brass necked up for my 7MM08. I am in early stages of using it but have not seen donuts form so far.
I will say this, you will enjoy shooting any of the 7MM rounds you choose. Especially when you enter the world of shooting heavier 162-180 grain bullets.
I have a 7WSM and use only W-W 7 WSM brass. I have it all annealed and then just load and shoot. Never had any issue with donuts being created with it. mine is not a tight neck chamber though.
I am now using Lapua 260 brass necked up for my 7MM08. I am in early stages of using it but have not seen donuts form so far.
I will say this, you will enjoy shooting any of the 7MM rounds you choose. Especially when you enter the world of shooting heavier 162-180 grain bullets.
Re: Donuts? For you 7mm guys
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: shoot4fun</div><div class="ubbcode-body">I have a 7WSM and use only W-W 7 WSM brass. I have it all annealed and then just load and shoot. Never had any issue with donuts being created with it. mine is not a tight neck chamber though.
I am now using Lapua 260 brass necked up for my 7MM08. I am in early stages of using it but have not seen donuts form so far.
I will say this, you will enjoy shooting any of the 7MM rounds you choose. Especially when you enter the world of shooting heavier 162-180 grain bullets.
</div></div>
Thanks for your reply. That's pretty much what I was looking for.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: shoot4fun</div><div class="ubbcode-body">I have a 7WSM and use only W-W 7 WSM brass. I have it all annealed and then just load and shoot. Never had any issue with donuts being created with it. mine is not a tight neck chamber though.
I am now using Lapua 260 brass necked up for my 7MM08. I am in early stages of using it but have not seen donuts form so far.
I will say this, you will enjoy shooting any of the 7MM rounds you choose. Especially when you enter the world of shooting heavier 162-180 grain bullets.
</div></div>
Thanks for your reply. That's pretty much what I was looking for.
