A Big 45 pad and a little oil does a nice job on rust. I have used it on some very old and rare guns and have not been disappointed. As with anything, go slowly for best results.
As for the bolt, it looks like someone already polished it. I would use a little Flitz to polish it paying special attention to a few areas to improve the bolt function. There are a few good videos showing the areas in detail.
My M-44 was very hard to open after the striker released even with no round in the chamber. Now, it opens with normal bolt gun effort and saved countless bruises on my hand.