Old design?
There are still Bell UH-1's flying but for those militaries that can afford newer aircraft they are usually replaced by Sikorsky Blackhawks.
Re the photos of the Gunner....tells me the aircraft is not designed for military use (Yes I know the USAF is buying some....but then recall the mission they are being used for....Missile Site Crew Transport).
The Gunner position in the photos is flat ridiculous and is only good for a laugh.
One thing that really stands out....is the empty brass collection bag (assuming that is what the OD thing on the right side of the door gun is just that...would be as useful as milk dispensers on a Bull.
As to aiming.....the short squirt and move the Tracers to the Target method works fine.....especially with a Mini-Gun.
Now...imagine what a Mini-Gun set up would look like on the side of that aircraft and how the Gunner would be limited in his ability to operate the weapon.
Then.....the most important issue...is the 139 built to a Military Combat Standard as is the Blackhawk?