I spent a few minutes today on my lunch break doing some weapon mock-ups for my DOOM Challenge entry.
For some authentic visuals, I chose to video myself wielding a toy gun, before digitizing it and adjusting it to suit my needs. From what I gather this is fairly similar to how id did the weapons for DOOM.
I bought a really cheap little Nerf gun from a local supermarket to use as the basis for the games pistol, and below you can see a screen grab from one of the video frames. Three frames were taken overall, to give a nice range of motion for the weapon recoil when firing. Bringing the grabs into Gimp, the background was removed and the gun desaturated, to remove the toy blue and orange colours. The bitmaps were then down-sampled and palletized using the original DOOM palette.
Finally, this was thrown over a screen-shot to check it for visual fit. It looks pretty cool to me, so I'll add some muzzle flash, and try to integrate it into the game. Of course i'll need to throw on a good measure of weapon bob when your walking for that full doomy goodness.