Hi Dave, use paint stripper and try and get as much off as possible, as long as its acting on the paint in the hard to reach areas it should loosen it up enough to allow the vapour blast to remove it, it is more for cleaning than paint removal but my barrel shown had been repainted in the past & was very patchy & it removed most of it leaving a few bits in the hard to reach areas inside the fins where i will get some nitromors in & have a go at it again, hope that helps.