I'm a big fan of 'let's identify the problem' first.

4/0 is about 400 grit, if that does not take care of it, there are coarser grades.

Or, you can buy a correct size chamber hone from Flex-Hone for about $40 and do as many as you want. The finish hone is about 400 grit.






"The price of good shotgunnery is constant practice" - Fred Kimble