Dennis, Wade, Whitebear;
Dennis; Frankly I believe "boiled blue" is a misnomer, what you actually get is a "boiled black." I fail to see any blue on my barrel, it is afterall red oxide changed to black oxide. In art blacks are created by beginning with a base of red or a blue and will reflect those base colors and be red toned or blue toned always, in this way you achieve a warm (red based) black or a cool (blue based) black. So, if we begin with red rust and boil it black it will retain some of that warm red in the form of a very dark brown undertone. On my barrel (and lock) you can readily see the deep down brown tones in sunlight. Otherwise it looks black as midnight and a bit overwhelming at that - I may end up scrubbing some of that off in the end. Waiting until I finish the stock to make that judgement.
Whitebear; I would love to be able to answer your question about the shotgun barrel but I am not that experienced in these matters and have no idea how that patina would react to boiling. My gut tells me it would turn black but I really can't advise you. Perhaps posting a photograph might prompt some of the more experienced builders to advise you.
Wade; if you believe you have screwed the browning process just sand it all off and start again, not difficult. When applying the solution you want to use a damp applicator (pad, rag, whatever - I used 100% cotton balls) not a wet one, squeeze it out. AND the pressure you put it on with plays a huge part in avoiding that copper toning - just gently wipe it on in one direction (as one direction as you can), do not press on the cotton ball as you slide it along. Overlapping is ok if it is just one wipe over an adjoining edge but don't apply more than one coat at a time. Card between each application after it rusts as much as it will (according to how warm and much moisture is in the air). The carding is important to achieve a smooth finish and avoid a caked up mess. When carding remove all of that red flakey stuff down to a smooth looking brown, then apply more rusting solution if needed until you are satisfied you have a good brown coating - a judgement call.
Dat's about all I know fellows.
dp