Well, I made it. I bored 1 inch long holes into a piece of really dense oak, with a 5/8 forstner bit. The holes had smooth enough walls which held up even to 700° lead. I used a hammer on an anvil to taper the slug at the back end, and drove it into the barrel. The barrels only . 61, so it was a hard job. I had to keep shaving the edges off of the bulging slug. But I got it in, and drove it back out, and I'm satisfied enough with how it looks. I have a question: the slug fits really really really tight, and the finest honing compound that I found with a quick search is 320 grit. Well maybe there is 8000 grit Forgive me but it seems like 180 would work fine, followed with 320 and then 600. I wonder if any honing compound will get between the slug and the barrel. Should I file down the slug a little bit(I don't trust myself to do accurate filing) so the compound can get between the barrel and the slug, Or do I now just slather the bore with grease borne grit, and labor my ass off? PS I only intend to get the bore a little smoother, I know I can't grind off anything like 1000 of an inch with this method. Also I plan to take the OP's advice and deepen the slug's grooves to preserve the raised rifling, Thank you for your consideration!