browning over blue

I have some plumb brown browning solution was wondering if you could brown a blued barrel with it.

Others here will chime in on this, but if you want a good brown, you need to strip the bluing first. I am pretty sure you will get some kind of brown if you really have the barrel totally degreased, but it will not be a true plumb brown. I am no expert, this is just my opinion.
Flintlocklar

One of the reasons bluing works so well to prevent rust is, it absorbs oil and holds it. As long as that oil is in the existing bluing, it will keep the steel from rusting further so, the browing solution who's job is making rust won't work well.
It can be made to work if the existing oil in the bluing is totally removed but this isn't always easy to do. Maybe a modern "disk brake cleaner" might do the job without destroying the bluing but most of the methods of removing oil will also remove the bluing.

I just removed blue and browned two rifles. Remove the blue with white vinegar … carefully polish barrel with wet or dry [at least 400 grit]. Then brown. I like the browning from Laurel Mountain Forge as it requires no heat and browns through grease. [follow their instructions … not cheap but excellent product. No, I don't own shares] There are instructions for removing blue with vinegar on this site. [Zonie can probably tell you where] Instructions are better than I can do, but it uses paper towel soaked with vinegar, wrapped around barrel and at least thirty minutes wait. It may take longer and require more than one wrap session. My barrels are a pretty chocolate brown. Polecat

Thanks, Polecat I can't get LMF up here they won't send it across the border.

Oh... sorry! Use what you have but the removal of blue is easy, messy, but I think necessary. enjoy. Polecat

thanks again

I was talking to my gunsmith friend the other day, he said he uses navel jelly to remove old blueing.

Navel jelly works good but if it is left on the surface too long it will etch it badly.
Most if not all of the commercial gun blue removers are milder and won't damage the surface as much.
As was mentioned, vinegar will safely remove bluing but it works best if the blued surfaces are degreased with disk brake cleaner, denatured alcohol, MEK or lacquer thinner.

Naval jelly will leave a phosphate finish that will have to be removed. Use Birchwood Casey blue remover. In the shop we used Brownells steel white that has to be heated in a dip tank, works great but for a 1 time use the BC.

Shop I worked at blued 100k's of barrels from new manufacture to old refurbs. Many have had our bluing on their commercial barrels.