Steampunk liquid propelled pistol

Ok, first attempt to colorize a pencil drawing. The original was just something that I made using a mechanical pencil, I scanned it onto the computer, and edited it with Gimp. I used multiple layers set on colorize, changing the opacity as needed, and blurred certain parts.

The gun is for a character of mine in a Tephra roleplaying game. It's a liquid propelled design. After each shot, the bullet chamber springs opens (that's the thing sticking out of the top of the gun), and a measured batch of propellant is automatically pumped into a combustion chamber (inside the gun). A new bullet is manually inserted into the chamber, which then closes automatically. The gun is ready to fire.

I had originally planned on making the stock ivory, but I couldn't figure out how to make it look right in Gimp, so I changed it to wood.

Anyway, let me know what you think.