check this out:
http://www.youtube.com/watch?v=LNrX9LFzjUU
Just follow the instructions in order to get the perfect results.
Dont use BW in a dump climate in a garage. Use it in an A/C operated area. I've blued a 1911 type barrel and other small parts, it looked great. I put several "layers" on the parts til I had the right dark color I wanted.
Overall - BW is a good blueing stuff w/o disturbing odor, but I would never use this stuff on a Luger