Using a 30 cal brush on the chamber will take quite some time. I use a 20 gauge bronze brush. This fills the chamber very well on the Mosin. Take the barreled action off of the stock, and use the brush and drill method with mineral spirits. What you most likely have is a build up of laquer from the cases mixed with cosmoline. There is a very good reference stickie on the surplus rifle dot cawm site, and also good information on the 7.62x54R site. Good luck.