Hmm.....


I'm thinking that you put the gun on a sheet of white copier paper on a sheet of glass (like a glass topped table). Shoot the flash from below the gun. This will cause the background to blow out but also cause a rim of light around the entire thing. Place your camera straight above the gun and shoot through a piece of white foam core (or some type of rigid, white material you can poke a hole though). This should bounce some light back at the gun allowing for detail to show in the primarily dark gun.


You'll definitely lose some contrast shooting in this way (as light is coming straight into the camera), but it might work out well. I think it's worth a shot. Note: You can also use an empty fishtank turned on its side if you don't have a glass topped table.