I was cleaning pockets and flashholes on a box of mix 7mm08 brass last night. And every Winchester stamped case had a donut at the shoulder and neck. Now this brass has to be from a client that used my range because I never have used win brass in the little 7. So I just threw it out there was only 11 of them. Is winchester brass known for this? Because none of my mix brass has it except the winchester and I have only loaded that box one time. So it's not shot out.