The Pistol is a sidearm weapon that can be bought as a replacement for the standard Blaster. While the latter is free and doesn't require ammunition, it suffers from a slow rate of fire and an even slower projectile speed, reducing a user's chances of surviving an alien assault significantly. Especially frontline engineers with a construction kit as their primary "weapon" will be delighted to hear that they can pack a semi-automatic gun with similiar damage output and precision as the standard SMG.
Concept art by alex_bo:
If you are modeling this beauty, you are invited to engrave your name on its side in the form of "O'Dowd & Name Firearms" (O'Dowd being the name of the concept artist).
Regarding technical specifications, aim for an upper limit of approximately 4-6k tris for the polycount. The texture should ideally be 1024 squared in a lossless format, like TGA or PNG. Required maps would include diffuse, specular, and normal. You can also make glow and gloss maps where appropriate.