I'm guessing this is the huey gunship that has been for some time on Simviation?
The initial had no working guns but there is a futher download adding a sort of gun fix. As I recall the two guns are fired using the gun and cannon triggers (1 each side). To get this working properly may require your buttons set up correctly.
I have the chopper but I have enough trouble getting up and down without worrying about shooting!!!!

Would like to I have a great idea for a mission using Nibbios ground troops!

I didn't have any trouble with the landing other than pilot error. Like all CFS2 choppers they are a sod to hover but I was able to land by coming in at 10knotts or so then pulling back and allowing it to skid to a halt.
Usually looks like it is parked in long grass though!

As for the rudder. I believe the real one was pretty useless as well. It does work but only slowly unless turning with the rotation of the blades (anticlockwise as I recall).

I am assuming you have auto-rudder switched off!

The main proble mI have with all helicopters is that the engine sounds only seem to load occasionally so I am usually flying in silence! I have several choppers all with different sounds.
Have you a similar problem?

Hope this helps but probably not!