What size bushing to start with

[Bulseyetom]

I am getting a wildcat 7mm Ackley Krag with a .309 chamber. I want to turn the brass so that I have a .306 diameter after seating a 7mm bullet. Should I get a .304 bushing when I have my custom die made or what size would you recommend? The wall thickness of the one piece of 30-40 Krag brass I have shows that I will have to turn quite a bit off so the brass should be of equal thickness. The rifle is based on a Ruger single shot so I am not sure if I need less tension but I expect the brass to last quite a while so I want to make sure I have a bushing small enough. This is a hunting rifle so I am not looking to extract the last 0.001 out of each group. Thanks for any input. Tom

 

[DCRYDER]

Thats the one I would start with. Its nice not to have to worry about cartridges getting battered in the magazine during recoil. I think .002" tension should be plenty.