you might be able to hone it out a little bit with a cylinder hone, just be cognizant of where the chamber and such are. There are the "balls on wire" type hones and also the 3 stone type hones.
a gunsmith in your area might already have the hones and do it for you for what the hones would cost.
a poor man's hone is a piece of dowel wood with a slit cut in the end. fold up some wet/dry paper and stick it in the slit, long enough to wrap around the inside of the barrel. oil the inside and spin the dowel with a drill moving it in and out of the barrel.
scotchbrite on a dowel will do the same thing
the above procedures would smooth it out without taking a lot of material out of it
just a thought and suggestion