I tried fire bluing a barrel today for the first time. I followed the instructions on Jack Brook's website.
It seemed to work pretty well, giving a fairly deep gray, nearly black finish on it.
The basic gist of the process is to stuff the barrel with charcoal to prevent scaling in the bore, get a good bed of coals going, put the barrel in the fire and wait till it gets red hot. Then "card" it with a stick while it is still in the fire for about 30 minutes. The carding, or scraping is intended to prevent/reduce scale buildup.
I have a pistol barrel from a CVA or traditions pistol that is my test barrel for whatever I want to try out without destroying a good rifle barrel.
Here is a pic of the barrel before, sanded to about 320 grit:
I crushed up some hardwood charcoal to put in the barrel, and I also put some in an Altoids tin along with a lock bolt as a test of charcoal bluing and/or case hardening.
here's the charcoal ready to put in the barrel:
Here is the barrel in the fire heating up. You can see the colors starting to come through yellow, brown, purple, blue. On it's way to working temperature.
I don't know if it ever got to the dull red hot that Jack's site talks about. He says its hard to see it in the daylight. It did go through blue to gray at least.
After it cooled, I wiped it down with a rag. The pictures make it look much lighter in color than it really is.
These are after rubbing boiled linseed oil on it. I only scraped the top three flats, and you can see that the finish is more even on the flats that I scraped. I could have done a better job of scraping, but my stick was burning itself shorter and shorter and it was a hot hot fire!
I think it was a success. I may try it on a rifle barrel. If so, I will spend more time being attentive to the scraping process to get a more even coat.
I'll try to get a better picture, because the ones above don't show the real color. It's much darker, and looks pretty close to what Curtis got on his Christian's Spring rifle when he charcoal blued it in a pipe.
Cheers,
Norm