If you want it clean it some more and don't have a lot of equipment you can use one of those powdered glass paste cleaners such as "Power Paste" on a 4x2 with a brass jag. They make a good substitute for Mottie's Paste and similar cleaners. I dislike abrasive cleaners on principle, but used in moderation they do the job when other things will not. If the bore is clean except for some spots of rust scale that you're concerned might cause bulging if fired as-is, then you could plug the muzzle, stand the rifle up muzzle down and fill the bore with vinegar, leave it sit for a day then brush out with a wire bore brush and very hot water. You'd need to remove all oil from the bore first though to allow the vinegar to work.
I agree with the above comments: the bore looks VG+ from a wear perspective.