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lapua brass doughnuts

rmist04

shooting a 273 neck in a custom bullberry ...one shot with lapua 6br brass and it forms a doughnut inside the neck...no prep work to new brass ... just fire forming to chamber. Why would I get brass flow from one firing??? My ppc did but only after several firings. Thank you for any imput !!!

OK...Nobody out there knows what I'm talking about or you have never noticed this problem !!! I thought I might have a bad lot of brass or something. Also...isn't this forum set up to help all shooters ???
Thanx have a great day !!!!
 
Re: lapua brass doughnuts again !!!

rmist04 said:
shooting a 273 neck in a custom bullberry ...one shot with lapua 6br brass and it forms a doughnut inside the neck...no prep work to new brass ... just fire forming to chamber. Why would I get brass flow from one firing??? My ppc did but only after several firings. Thank you for any imput !!!

OK...Nobody out there knows what I'm talking about or you have never noticed this problem !!! I thought I might have a bad lot of brass or something. Also...isn't this forum set up to help all shooters ???
Thanx have a great day !!!!
Click to expand...
 
The only thing I can think of is your headspace. A little more info would be helpful. I'm sure someone else will chime in.
 
Is your custom Bullberry chambered for a 6 BR Rem. or 6 BR Norma ? If it is a 6 BR Rem. you might have to trim some length from new Lapua brass before firing . Other than that I'm not sure why .

Rodney
 
rmist04.
Every piece of new brass I work with has a donut that I remove when I neck turn, even the 284 cases I make by expanding the necks of 6.5X284 Lapua brass to 7mm. K&M makes a carbide pilot that cuts through the donut as you turn the neck. Fireforming doesn't make the donut found in new cases go away. If you have a no-turn neck, you can still ream out the donut with the K&M pilot. Just set the cutter so it doesn't touch the brass. Otherwise, you have to seat the bullet out in the neck so the shank stays out of the donut area. This may not be possible with your chamber or action.
 
I've noticed them in a 6BR Norma with .272 no turn neck with Lapua brass. 4th firing and its definitely there. Does it cause a problem? I don't seat a bullet that deep and I don't use a sizing button on my Redding "S" dies, so I never touch it. It is a pressure restriction but I doubt it causes a real problem. But I do have a K&M neck turner ordered with carbide cutter mandrel.
 
I doubt it causes a problem if the bullet is seated out. I think the issue is uniform neck tension. The donuts don't feel the same when the cutter cleans the out so the donuts may make your neck tension less uniform.
 
TonyR

I’m a “newbie” at this and am a little confused about this “donut” thing. I just got a 6mmBR Norma rifle and have ordered Lapua brass because I was told it was the best you could get. Are you saying that there is a good chance there will (could be) be a problem with “donuts” in the new brass when I get it, and that I should use the K&M reamer to clean them up? At the price of them you’d think Lapua would deal with this before the brass left the factory, however as I said I am new to this so perhaps it’s common place. Is this normal and just something they expect the end user to take care of.

I assume this carbide reamer would be very caliber specific because you would not want to remove any metal at all from the inside of the neck other than the “donut”. Or am I misunderstanding what’s happening here?

Sorry to ask questions about issues that may seem so obvious to most of you guys.
 
1972.
Not a problem to ask questions here and your questions are good ones. I have had the expected fine performance from Lapua brass. In my opinion, what makes Lapua the best is the consistence and durability of the brass. Actually, I believe that RWS brass is better than Lapua, but you can't find it in the US in the calibers I use. What makes donuts, i'm not sure, but I think it is something that happens when the neck and shoulder are formed on the case. As the diameter is reduced, the brass has to go somewhere and I guess some of it ends up in the bend where the neck and shoulder join. I believe that all brass suppliers share this problem. The K&M tool I described is a carbide neck turning pilot with a special cutter in the end of the pilot which only cuts what is in front of it. It does not ream the neck like a Wilson neck reamer does. K&M sells a companion expander mandrel for each caliber that will open your neck up for a nice tight fit on the carbide pilot. The neck slides smoothly over the pilot until the cutter end reaches the "donut" at which point you feel a little resistence as the cutter cleans out the donut. You do have to be a little careful when the pilot is inserted and removed from the neck because it will score the inside of the neck if you cock the case.
 
rmist04,
This forum is set up to help shooters, especially if they keep current with posts others have left.
 
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