Dumb question but I've totally forgotten. I will be sizing a 405 grain to .460 using the Lee sizer. I'll only be lubing with the LAM and the H & H sizing die I have is 459, so I want to open it up to .461. IIRC I used a dowel and some fine emory, perhaps with a touch of oil. I went bit by bit and at some point it was perfect. I just can't remember what I used to determine when I'd opened the die out to the right dimension.
I have calipers for outside dimension but nothing for inside....how do you guys do it?