Check that the screws for the scope mount are not dragging, if you have a scope mount on it. Sometimes they can cause grief.
Guys have polished up bolts with toothpaste. Sit and watch a movie, and work the action back and forth. Clean, repeat as required.
You can learn a lot about where it's dragging by marking up the bolt with magic marker or a sharpie pen, and running it back and forth. Look at the worn off spots of marker to see where the stuff is rubbing. It can give you an idea, anyway.
I'm loathe to suggest metal polish, but if it were mine, I'd probably grab some Solvol Autosol and have a short go with it, then clean it out and check it. One of those things that is gonna require use of some judgment on your part.
Cheers
Trev