Hi David
This gives a good idea of what you need to see before you rust : -
http://www.youtube.com/watch?v=vuP4m6L95K4
We're creating the rust in a different way to Mr Pottersfield but the rust formation and boiling time is just the same.
The powered wire brush is a bit of a no go for airguns as their actions tend to be a bit more complicated than that of a cartridge rifle or shotgun so I stick with wire wool.
I'm not bluing an action at present, I'm bluing 6" lengths of 12mm hydraulic pipe as a test --- these make excellent test pieces as you can spin them up in a drill to polish them.
Doing a few test pieces is worth trying as it gets you used to the process and also shows up any problems before you move on to a gun --- so far my test pieces have shown that my new heated cabinet is scrap and that I need to build a bigger one.
All the best Mick