Originally Posted by skires
I'll have a play with the heat shrink.
Finish with the finest.
Good luck with your challenge!
Do you have any appreciation re how much material you are trying to remove to clear to the required degree the "choke" at the breach end?
My concern based on many years experience hand lapping engine valves and diesel injector discs to various degrees of thou tolerances - material removal is hard to achieve without a solid metal to metal interface and a compound between same.
I am concerned that using a felt pad and compound will just be a journey in patience with little reward if you need to remove material as opposed to just polishing what is there.
Just have a picture of a skeleton holding on to a cleaning rod and a barrel metaphorically "shrugging its shoulders" in my mind.