A basic minigun with a minimum of detail added, sat on top of a tripod with extensible legs. Not terribly accurate but then it's a representation as opposed to an accurate model.
The model made use of extrusion along spline path for the adjustable locknuts (see below), and also a fairly successful boolean "fudge" - where the barrel separators are you could see the divider in the barrel itself. A simple cylinder was created which was the length of the front and rear divider to boolean out the material so the barrel would appear hollow. Much swearing was involved as the original barrel positioning was done via approximation as opposed to using the transform tools to rotate to exact locations, also the centre of rotation was not in the absolute centre.
The two shots below are of the completed minigun. As you can see, the level of detail is very basic. Missing is the ammunition feed chamber, ammunition belt, and several other weird and wonderful sticky-out bits.
The image on the left below shows the barrels which have been hollowed out as a result of the boolean operation. Admittedly this created several artefacts within the barrels which were a complete pain in the arse to correct with a cap procedure. The image on the right is a view straight down the barrel. Obviously.
A pretty piss-poor close up of the nicely curved telescopic leg adjuster. As stated above this was modelled via creating an arc and extruding a cylinder along it (Extrude along spline path option). This method could be used to a certain extent to model the ammo belt if you have the patience.
Shot of the minigun attachment to the armature. The four spindly things were added as a detail afterthought.
Download the final minigun scene.