Unless you are really sloppy, the holidays are mostly in the pigment anyway.
None, actually. There's lube/graphite/carbon coating the bore from previous shots. The bire is pretty dry when using powder coated bullets.
I think the only bare spots on my lubed bullets is IN the lube grooves. I can only tell once some bullets begin to show some "patina" or oxidation. Some do get hung up on filling lube grooves when "tumble-lubing," but the lube IN the grooves never touches the bore anyway - at least with bullets having a traditional lube groove. My lube coating is THIN, but it's thorough. Even ones run through the Lyman 45 get a very thin coat of "grease" on the bearing surfaces, as evidenced by the lack of oxidation over time, whereas noses do start to change color.
We shall see soon how I do with bare spots using PC. I'm not gonna lie - I don't like ugly bullets. Mottled bullets may work just fine, but it will bug me.
Anyone know if you can buy Eastwood powders any place but directly from Eastwood? They want $26 to ship ONE pound of powder. I don't mean to be too much of a cheapskate, but I do try to keep an eye on the cash outlay part of casting since I invest time/effort in lieu of cash. "Free bullets" are like "free firewood" - ain't no such thing.