Ok, I "know" what it is; but I dont know why (what it does that regular bullets wont do?) If I would normally use a 458 size bullet, what size should I use with a Paper Patch?

Im looking to load 45-70 and if I get bold 45-120; but thats on hold for a bit. Im also playing around with some others (38-55 and maybe 405).

Ive been told that I need special paper and others that say "regular" paper is fine and even cigarette rolling paper BUT none of those guys actually load Paper Patch???

HELP