Usually one starts .002 over bore dia. with a cast lead bullet. This often gives the best accuracy. It will of course raise pressures some, but usually you are not pushing a cast bullet any where near pressure levels where you need to worry about it. Pressures can also be changed with bullet hardness. The softer the bullet, the higher the pressure. I would start with .310's out of wheel weight material. Use the books starting load and work up. Good shooting.