Donuts in 6BR

[HPMike800]

Has anybody had donut problems in a staight 6BR?

I have never heard of the problem in this cartridge, but after 6 firings I've got one in every case I checked. The only thing I can think of is that I'm shooting unturned Lapua brass fired in a 0.271" neck chamber. The neck is a little tight but it has worked fine. I do think it has limited my velocity a bit though as I seem to have to run a little lighter loads than most.

Any thoughts?

 

[TonyR]

Mike.
I have to turn my necks before I can shoot and every piece of new brass i have prepped has had a donut, some more, some less. Here is the link to a thread where donuts were discussed recently. http://www.accurateshooter.com/forum/index.php/topic,3748131.msg35864804.html#msg35864804
I believe that the donuts are there in brand new brass but they might not be noticable if you don't turn necks or if you seat the bullets out in the neck.

 

[HPMike800]

I read that thread.

Does anybody know if the K&M reamer/pilot will fit into a Sinclair turner? What tool does the RCBS pilot/reamer fit into?

 

[TonyR]

The shank that locks into the K&M tool is 0.3432 inches. I don't have the Sinclair to measure. You would most likely also need the K&M expander to work with the K&M pilot. I believe that the diameters of the pilots for the Sinclair and K&M are different because the respective expander mandrels that are sized to work with the pilots are different diameters. The Sinclair expander mandrel is 0.2423 inches while the K&M is .2437 inches. I don't have a Sinclair turner pilot to measure but the K&M 6mm carbide pilot is 0.2442 inches. Assuming the same spring back by the brass, I doubt that the K&M pilot would work with the Sinclair expander. I have found that proper fit of the neck on the mandrel is one fo the keys to even neck walls. Maybe someone else could give you the Sinclair dimensions.