Best way to achieve this

Hi guys:

i want to put a 3d rifle and make it rotate a little, just to show it and later make it shoot a bullet and with its smoke make a name… it does not have to be that flashy (its for a college presentation) but i want it to look cool. Any help on how to achieve this and where to find a 3d model would be greatly apreciated… thanks in advanced!!

:link: