After lurking this forum for quite some time, now I think that this is my turn to give my own effort to the comunity.
Here's how to play light gun games with the most accurate light gun you can get on your PC.
Requisites: VR headset + controllers (I own a HTC Vive, but I think that it works also on the Rift and WMR) + virtual desktop app (search it on steam; maybe other similar apps will do the job)
That's very easy:
1) install virtual desktop and launch it
2) set your virtual screen size, distance etc. as you like. This will be the screen where you will play your favorite light gun games
3) in input options, untick these boxes: "show lasers" and "show contacts" unless you want to see where you are aiming on the screen while playing (the last option was added by the author after my personal request, hehehe)
4) now keep VD running, and launch the light gun game you wish to play (just make sure that you previously set the mouse as controller in the game). I suggest to launch the game (or the emulator to play your game) by using the keyboard and the computer screen, since at the previous step we chose to hide the mouse cursor
5) put on your headset and play the game, shooting by aiming directly at the virtual screen with you favourite VR controller. Virtual desktop emulates the mouse with you VR controller, which is fast and accurate.
Have Fun and let me know how you like it!
A FINAL NOTE:
** BEFORE ** launching VD, you can select a different virtual model for your VR controller other than the regular ones resembling the real ones. For example, you could choose a gun model to aim down the virtual gun's sights while playing; sadly, currently there a few gun models in steam workshop, and none of them is much suitable for our purpose. It would be nice to have some proper gun models to choose from, with accurate gun sights.