Step #8:
Rust-brown the barrel.
Product used is the Birchwood-Casey "Plum Brown" solution, arrived today courtesy of Amazon.
The barrel finish wasn't quite as pristine as appeared at first glance, so first move was to do some polishing. Bluing is only going to make surface imperfections more noticeable. Then thorough degreasing; I like to use acetone, followed by denatured alcohol.
Then I made a little stand for the barrel from a piece of dowel and scrap wood:
The instructions say to heat to about 275 degrees until a "drop of water splatters". I did that in the oven. It's surprising how long it takes. But this is a pretty big hunk of metal. Note: use distilled water. Tap water will leave a mineral deposit.
Another note: the solution could spatter while applying, so wear long-sleeve shirt, gloves and safety glasses.
Yet another note: be sure to plug holes you don't want rusted, like threaded holes.
I was surprised how much color change occurred so fast with the first coat. I suspect you could still get good results at a lower temperature.
The instructions didn't say to do this, but I made a neutralizing solution from distilled water and baking soda, swabbed that on after the first coat dried, then rinsed in cool water.
The first coat may not look like much, but I'm going to let it alone overnight and then card it. To my eye, it looks pretty good for a first coat: