Extractor wisdom
I have a Ruger Mk II pistol I use exclusively as a suppressor gun. Cut to 3 1/2", and it gets disgustingly dirty inside, quickly.
I thought it was decently clean inside, but I was having failures to extract. Turned out there was enough plaque-like carbon buildup on the breech face, it was holding the bolt off a few thousandths or so, and the extractor was not fully engaging.
Scraped at it with a pic, and flakes of black stuff came off. And the extraction issues seem, so far, to be gone.