I seldom sand a barrel for browning. I carefully draw file it parallel with the barrel length til all major scratches are gone & all fine lines are parallel with barrel length, using a fine metal file. DOne carefully & with some practice, it will look as good as if you sanded it.
Then I Bead Blast the barrel & parts, then get it washed for browning.
Also sights have been removed from the barrel, disassemble the lock as well & do all the small parts when ya brown the barrel.
I card everything with a Dixcel Wheel from Brownells, mounted in a drill clamped in a vice at about 1000 RPM. Light pressure on it & just card the rough off raised rust & recoat the browning solution.
ALL is done in powder free nitrile gloves, even the doorknobs ya touch must be Clean.
All browning done in a steamy bathroom @ aprox 85 deg or warmer works the best for me.
In winter time I put a small electric heater in the bathroom to keep the temp up. Block off the air cond/heat duct.
I lay down an old shower curtain, them a large piece of brown paper, then 2 pieces of 2" x 2" about 5" long to support the barrel off the paper.
Apply solution to bottom 3 flats of barrel first & underside of tang, flip it over & do remaining flats. I use a cotton ball barely wet with solution so I can just tell I just did wet or wipe the barrel. Do not want puddled or sloppy wet solution on the steel.... just barely wet enough that you can visibly see you rewet the barrel.
Apply the browning solution in Long even strokes parallel with the barrel.
On small parts I use a cotton ball & a Qtip to get into the tight crevices.
The first 3-4 applications will look like manure. Just hang in there & keep doing it, it will get better. Don't stop at 5 or 6, as you may have a place not browning as well & you cannot see it. Usually by 6th application is looks great. by 7 you have it done, one more just for a secure job.
I card every 3 hrs for about 7-8 applications. Thus all can be done in 24 hrs & then kill the browning process & rub it down good each day twice a day for 4-5 days til you are sure.. it has stopped browning, then start putting it all together.
Remember Clean, Clean, Clean... is most important with most browning solutions. With some solutions, any oil from bare fingers, grabbing the contaminated doorknob, touching the oily trigger on a drill, etc. then back to the barrel :shake: ya just screwed up big time & may have to start over. I am told this is not the case with LMF, but I don't use it so cannot comment on that. I have been using Tru-Brown on my rifles to be browned for the past ? 10-12 years & with good success.
If you have the barrel slick, IMHO it will not brown as easily or as uniform as if it were draw filed or sanded with a 220 grit with a small flat block of oak backing the paper..
Your mileage may vary..
Keith Lisle