“Doughnuts” have little to no effect on accuracy if you have a chamber that allows the pressure ring on the bullet to be seat above the neck should junction. ( where the “doughnuts” live )If you do have chamber that will allow this, it’s hit or miss that the loaded round will still fit in the magazine. ( assuming you handload )
It’s only a couple or so of the latest cartridge designs that take “doughnuts” into consideration. 300prc comes to mind.
It's one of the reasons for David Tubb's 6XC as well--which is the .22-250 necked up and with the shoulder also pushed back. It will fit in standard shot-action magazine about 2.85 inches long, and even 115-grain high-BC bullets won't seat down into the shoulder/neck junction.
