It is likely but it's also possible the chamber is a little rusty and the added pressure of the extractor is adding to the problem. Most who clean don't clean the chamber seperately and it is indeed a seperate step. I use a worn brush wrapped with steel fur and spun in a drill. The 0000 steel fur won't camage the finish, indeed it will improve it most of the time.. Be certain as usual to avoid allowing the center wire of the brush contact with the chamber or the bore at the throat. A little WF40 will help a lot.. clean the area well after to remove crud and steel wool particles..
