Yeah but when you are moving the ironsights of your "real" weapon, the on-screen sights would be static while yours would move over the screen.

I can see it working with the "free floating mode" crosshairs and a large center zone where the view doesn't shift. If you could scale the TrackIR inputs correctly, you would then be able to move your real ironsighs screen left-right and have the white crosshairs follow them - disable the on screen items, and you can shoot trough your "real" plastic ironsights.

Not sure what happens when you turn the body around, change walking directions or stuff. Anyone willing to try this with an airsoft pistol or the likes, just to see if it's basically possible?

To make it perfect, you'd need some kind of wireless trigger on the gun (can maybe be ripped from a wireless mouse or powerpoint presentation control) and ideally some kind of movement control, like a small joystick or pad under one of your feet you can move forward, backward, strafe and turn with. I think Arma does support joystick input to control infantry movement?

I've been looking to buy TIR for flight sims - if this can be used in such a way in Arma and maybe other tac shooters, even better. But it would be cool if someone could try the basics of it with a plastic gun or something.

There's also a "Light Gun" out that works with LCD screens, called LCD TopGun - but it is wired, much more complicated setup and much less versatile.