Unfired rounds often get stuck in the chamber.

[Troutguide]

This sounds very similar to an issue I had with Wolf ammo in my Howa 65G. After shooting a bunch of Wolf rounds started sticking, I was told by some it was melted lacquer but more research showed it must be carbon from the steel neck not expanding and preventing blow back. A good cleaning helped but carbon deposits are tough I need to get a better brush just for the bore. The reamer might be useful if you were very careful not to remove metal, just carbon. There are a few threads about stuck rounds lately, all have one thing in common: Wolf steel ammo. It is nice at the price but a pain to keep clean. Glad you got it cleaned up and shooting well again.