David,
Thanks for the pictures and information. I am caught up in several "firsts" for me. The first "first" is that I am trying to use ferric nitrate but dissolved in ethanol rather than water to minimize grain raising. When initially mixed, the solution is a nice deep reddish amber color but perfectly clear. If I use it fresh, I get one color after heat blush. If I wait overnight, the clear amber solution clouds up with a brown / rusty looking precipitate, fully suspended in the solution. If I use it after it clouds up, even on the same piece of wood, and then heat blush again, it comes out a different color. However, when testing in the barrel channel, neither one are very attractive on this piece of wood. Both versions come out a chocolate brown and too dark. This first ferric nitrate solution was 2 grams of ferric nitrate in 25 ml of ethanol. I'm going to try making a solution half strength and then try this all again.
On top of the ferric nitrate experiments, I am working with a couple of colors of TransTint....a few drops mixed in a 50 / 50 solution of ethanol and lacquer thinner. The original intent here is to do something with the blushed ferric nitrate and then try to get close to the color of Jim's rifle with the TransTint as an over wash. But there are about a gazillion permutations and combinations here....and I'm running out of bare wood spots to test on.
I'll keep you posted.....but this could go on for a while. This is the first time I have ever tried to get close to a particular color. Usually I just use the iron nitrate in water (prepared from nitric acid & iron), heat blush, and let the color come out where it will.