As I'm assembling my models, I can't get over the fact that the placement of the .50 cal off to the left side of the hatch would make it impossible to actually use. It's too close to properly operate and I don't see how a guy sitting to the right  and slightly in front of it would be able to shoot to forward, or really any direction other than left. The sticks out to me because most everything else about the walker designs in Dust seems to be very well thought regarding actual functionality and usage. 

Is it supposed to be an automated gun?

Other than profile pics that show the gun as placed on the model, the only other thing I can find is the box cover to the original coffin box, which shows a guy manning the gun, which appears to be directly in front of the hatch. 

Any fluff explanations? Otherwise, I'm trying to figure out how to mount the gun in a more usable position (which would correspondingly require the light to move as well.)

 If you look at old WWII footage, you can see tank commanders getting out of the turret and firing the .50 from the back of the tank, behind the turret. Guess the turret was designed off the Sherman, and retained the mg in the same spot. My guess is that the gun is there as an anti-aircraft mount.

Or the forward facing hull-mounted mg covers the front flank, the turret mounted one covers the rear. 

Midgettem1 said:

Spot on.  The real Sherman tank had a .50 cal mounted behind and to the left of the commanders hatch that was intended for anti-air craft defense.  It was not suposed to be used in battle as both the hatches would be buttoned up.  Dust walkers take a lot of design ques from the historical sherman, including the placement of the .50 cal mount.

Here's a pic of a late war M4A3E8 "Easy 8" sherman with an almost identical mount to the Dust turret:

 Thanks, guys.

I also found this clip from Band of Brothers. (I'm having trouble linking it, search Youtube for "Band of Brothers: Carentan Counterattack and watch from 6:00 min mark.) A post on DakkaDakka discusses whether the gun was actually fired in an anti-personnel role from the back of the tank in this manner.

Either way, it looks like Dust chose the wrong turret variation to model (there are many!) because there's no way the .50 cal on the MCW turret could be used in either an anti-personnel or anti-aircraft role, primarily because there's nowhere to stand behind the turret.

Argh, that bothers me. Now I need to see if I can mount the .50 cal somewhere forward of the turret. It just so happens that the 'claw' shape of the mount will fit right on the raised circle just forward and left of the hatch. Not perfect, but better. That ill require the light to be moved, too.

I had a broken M2 mount, so I moved like you suggested, here's how it looks…

 Thanks for the pic, Miah999. I think the gun looks reasonable there… at least better than it does where they want it mounted. I'm still trying to think of a way to make a traversing ring around the hatch for the gun to mount to. If I can't, I'll put in on the circle like you did.

But the best thing about your pic is is made me realize I could open the hatch! It was lied closed but popped right open with a little pressure via a pen from underneath. Thanks!

I seem to remember some fluff piece somewhere that stated MCW ma deuces were "remotely fired" from inside the cockpit. This write-up is not in the original OP: Blue Thunder book that comes w/ the OCS, so I'm not sure where I saw it.

Paolo Parente's DUST site, mebbe?

 Remotely operated guns isn't too out there for WW2. A number of aircraft had remotely operated turrets. The most famous probably being the American P-61 night fighter (remotely operated dorsal turret) and the most unusual probably being the Italian P.108 heavy bomber (remotely operated turrets mounted on the wings, the end result is something that looks like a 'boss' from an old arcade game)

LotusPwn3r said:

I think that may be in the DUST Source Book as well, and looking closer the would have to be remote op, as the have no handels (which are removeable from the real M2, but they pretty much impossiable to use without them.) The B29 also had remote turrets.

It is the Luther chassis that is said to have a remotely-operated MG.