Variation on chore-boy: most marine stores and some well stocked paint stores/depts have bronze wool, usually in three grades. It wont leave rust stains on your teak decks or remove blue, but is very aggressive on lead. A prior soaking with kroil works great but I've only done that in the bores. No reason it wouldn't work on cylinder faces too, I would think. For bores use a well worn brush or one a size smaller than the bore or you'll be using gorilla grease instead of elbow grease. The brass wool is a little easier to use than chore-boys but both work great. Lloyd Smale's comment about not getting bore leading is correct. Something isn't right with bullet size, hardness, bore conditon, load or combination of these factors or others i've forgotten. Veral Smith of LBT has some interesting comments on the topic in his book.
