If you want to try and remove some of the pitting you can make a slug for the barrel. Its easy to do. first put a wet patch in the bore about 5" down then degrease a brass brush of the proper caliber and put that in the bore leaving about 1/4 of it sticking out so as not to get lead on the threads. Get some lead good and hot and pour it down the barrel enough to go all around the brush. The lead will cling to the brush but not the steel. Let it cool and when you pull it out you will have a slug just for that bore.
You can use it to lap the bore with the JB compound. Just be sure to line up the rifling when you put it back in. (don't forget to take out the patch).
Take extra care if you have a fiber optic front sight so as not to get any hot lead on it or it will melt. I would wrap a wet cloth around it.