Making a gun

Hey, the task at hand is to make a model for a game with a 10,000 tri limit. The first task is simply to show what i can do, as such i'm aiming to make a gun (it's a pun) for the generic sci fi shooter genre of the current gen. Reviewing multiple concepts, i have decided to work on an original concept taking ideas from various places to create a Frankenstein monster rifle/ flame thrower.

 Here's some inspirational images that i have borrowed ideas from.