I am working on a steampunk style outfit and I decided to try and make some quick steampunk guns. I grabbed 2 squirt guns and 1 nerf gun and went at them with sandpaper and some paint. The blue didn't turn out as well as I had hoped so I may change that later on. I was trying to amke a death ray type gun but it didnt turn out as well as I thought it would. I know they aren't perfect but for my first attempt I think they turned out fairly decent.
I think you should colour up the screws in the revolver (yes, it is the best for the setting, I think), for extra detail. Darken the lines a little as well.
I just sanded off the logo's and I removed any stickers. Than I sprayed the whole thing one solid color. (in this case gold) Than I went in with some acrylic paint where I wanted a different color (blue,black,brown,and silver in this case) and than I used a technique that someone showed me to antique it. I took some antiquing polish and mixed it with some black acrylic paint at roughly a 50/50 ratio. Than I painted that on and took a old shirt and patted it off which left the old/used look. Than I did some touch up painting here and there.