Will you be putting a Holster on the belt? If so, add a couple inches to the length or it won't fit. I have a 38 inch waist but the cartridge belt I use for Cowboy action shooting is 44 to the center hole with a left and right holster. Just want to save you some grief .
Not sure where you're located, But I get all my cast bullets from here, Good prices and great service.
https://bulletsbyscarlett.live-website.com/
Tell her I sent you.
A surefire way to remove the carbon ring is to shoot a couple cylinders of ammo loaded with a full charge of Black Powder. then clean and oil as required.