Rember the mustart experiment.

[Crow#21957]

This works really well for me. No mustard. I took my polished lock and hammer and rubbed Birchwood Caseys Permanlue on them. Let dry well. Took steel wool and sprayed with oil.I use LPS but any oil.lightly rub surface of lock and hammer.
This is a real nice medium/light grey color.The pic does not do justice to much glare but trust me this is a very uniform and just the right grey to me. Looks so much like the gun metal grey. I'm going to do all the metal in this next gun. I put the breech plug which is just the raw steel color for comparison.

 

[necchi]

Cold blue products are mostly a copper/cupric sulfate that reacts topically with iron and turns blue in color.
There is no reaction or color change to the iron,, there is only a change to the copper solution on top of it.
Removing some of the copper will change the shade of that reaction with it's background.
It lends whatever color is desired,, but the process will need to be done over and over through the years.
The smell of "pennies" on an old gun is an obvious clue that cold blue has been applied.

 

[cynthialee]

Cold blue products are mostly a copper/cupric sulfate that reacts topically with iron and turns blue in color.
There is no reaction or color change to the iron,, there is only a change to the copper solution on top of it.
Removing some of the copper will change the shade of that reaction with it's background.
It lends whatever color is desired,, but the process will need to be done over and over through the years.
The smell of "pennies" on an old gun is an obvious clue that cold blue has been applied.

all my guns that I refinished have that smell. I love the look that the cold blue gives.

 

[azmntman]

I prefer a brownd barrel but 90% of mine are blued.

 

[SDSmlf]

all my guns that I refinished have that smell. I love the look that the cold blue gives.

If you are getting the look you want, can’t ask for more. There are other methods to get that look, but you may not have the time for the 100 year wait some may require.