I recieved my Act Labs PC USB Gun today, which I had preordered several months ago. Initially I was excited at the possibility of finally being able to play Police Trainer with a well calibrated gun, iun the provacy of my own home. It quickly became aparent, however, that this was not to be.
It would seem that using a CRT monitor does not guarenty that the gun will actually work. I have a 19" Dell Trinitron, and when I attempt to calibrate the gun the screen turns black (with light white bits at the top and bottom). This is at a resolution of 1280x1024@85hz, well within the Gun's range. But just in case, I tried all the available refresh rate choices, to no avail. So then I went through all the rates at 640x480, and had my best result with 60hz, which produced a medium dark grey calibration screen. This still wasn't enough to allow for a successfull calibration though, the gun still only manages to shoot the bottom left, right, and top right corners of the screen.
Suspecting my gun may be faulty, I tested it on a much older, much smaller, much crappier, CRT. The calibration screen was white even on this monitor's highest posible resolution (1024x768@75hz). So I tried a bunch of other things, from changing display timing formulas in the NVIDIA control panel, to cranking the brightness and contrast, but nothing worked. The gun remained unusable.
So I'm writing this as a warning to others who might shell out $80 for the gun. If your considering buying one, you may want to instead look at Guncon2Mouse, a TV, and a $10 Guncon2.