It involves tweaking the ammo, damage and other properties.http://developer.valvesoftware.com/wiki ... ng_a_model (Exporting)(XSI link at the bottom)http://developer.valvesoftware.com/wiki ... ng_a_model (Compiling)This should help the export side of things and compiling them, and thus actually getting them into the engine.The bulk of the work is modelling and texturing the weapon.