Hi all I picked up a rifle that is need of some TLC from my brother in laws dad. The gun had pit and rust marks on the barrel, which I removed with some steel wool and noticed that the blue finish was damaged(I can see metal in places). Is this something I can fix with a product or would it be best suited to take to a gunsmith. The gun is in good shape otherwise(the normal bumps/bruises) but tight.

Any tips or products would be much appreciated.

thanks