I agree that a cold blue is not going to hold up even if you use the best available (Oxpho) since this area is subject to holster wear. There is a way to fix it and not send it off to S&W for $250 bucks. The pits have to be removed and you are fortunate that the damage is confined to the end of the barrel. Polish out the pits by hand (NO Power tools) with small squares of progressive grades of abrasive wet/dry paper and proper backing.With those pits 150grit would be the starting point.You need to take it to at least 400 grit.The scratches from pit removal will be polished out.Confine your polishing to just the damaged area and leave the rest of the barrel alone.When you have a smooth pitless surface degrease well with lacquer thinner and acetone .Be sure to degrease the bore also. This will be a spot Rust blue procedure. If you are not familiar with this it is a simple procedure that you can do on your kitchen stove.Use an old pot and boil some water deep enough to submerge the end of your barrel past the damage.Heat the polished area with a propane torch too hot to touch and apply a rust blue solution ,Mark Lee`s Express Blue available at Brownells is my favorite. There are several different brands out there, all are similar chemical(acid) combinations.The polished area will immediately rust and be reddish in color.Submerge the end of the barrel in the boiling water for a few minutes.The reddish color will change to black and be sooty.Now with degreased 0000 steel wool (use the acetone to degrease the steel wool and let it dry throughly before using) gently remove the sooty residue.This is called "carding" and there are special brushes for it but with this small job the steel wool will work fine.At this point the polished area should be a dull gray.Do the procedure again:Heat,apply,boiling water dunk and card.How many applications? Different steels take the finish differently.Probably 4 or 5 or until you see no difference in the darkening of the finish. The last step will use the cold blue (Oxpho creme formula also available at Brownells). To help blend the finish and impart a bluish color to match the rest of the barrel again heat the newly blued area with the torch and liberally apply the Oxpho creme.Don`t let it dry out but let it work for a minute or two.Now burnish the Oxpho with a wad of the 0000 steel wool.Really bare down and polish it. If the brightness does not match up with the rest of the barrel after this, burnish again with a small square of cardboard. Oil with a good quality gun oil and you are done. Don`t forget to run an oiled patch down the bore.One last thing be careful not to touch the affected area during the procedure with your bare hands as it can leave oil residue.You have a fine revolver for the price and with a little effort it will be even better. Good Luck. Joe