Jenks,

Get some Kroil, saturate a patch (and I mean saturate) then pass it through the bore and leave the rifle stand overnight. Saturate another patch and pass it through, leave it stand overnight. Then pass a bronze brush through a couple dozen times and pass a few dry patches through afterward.
Give your bore 50 strokes with a patch smeared with JB, and then do another 50 strokes with a fresh patch smeared with JB. After that, run a few patches saturated with alcohol then clean with your choice of cleaner and dry. You shouldn't see any more rust, Kroil will literally creep underneath rust and loosen it, the brush will help and the JB should polish the bore. If you have pitting afterward, then you'll still have pitting but your bore will be much smoother than it would have been. Pass a wet patch of Barricade or your choice of rust preventative oil through and your good to go til' next time!

BPS