Heres what I would do.
Fireform your brass and check to see if they blow out to what your chamber cast showed.
Then measure the inside diameter of your formed brass. Thats what you patch up to. Deduct .008 and that will get you to the biggest bare bullet diameter your chamber will allow.
Depending on your chamber throat and the ogive of your bullet, you may find that the bullet will need to be seated well into the case rather than way out to avoid pushing hard into the lands.
My guess is that a fire formed case will accommodate a .468 patched bullet so a slick of .460 will be about what you will need for a patched bullet that will slip snugly into your fired cases.
A bullet like this will work with black powder and will be appropriate for NfB loads as well.
Last edited by Huvius; 12/08/17 12:45 PM.
