I was finally forced to get the 37" Mitsubishi Multisync out of my living room (wimmins

) and thought "what better time to set up a gun / dance platform system?" So I moved it into a freshly emptied part of the shop, built a monster of a stand to hold it, skinned it with printed vinyl, skirted in the stand with some nifty material and put about $100 worth of audio activated lights around it (for the dance / guitar games). Probably doesn't qualify as a full blown project around these parts, but with a PS2 connected in true RGB and a couple of Guncon2's with virtually every compatible gun game ever released, I'm satisfied. The GunCon2's are dead accurate on this setup, and it looks acceptable considering the time I have invested in it.
I have been hoarding this particular monitor for this purpose for years because I had an awful feeling that this was going to be the only way for a long time to get really good shooting game satisfaction. At least until some really new technology comes along to replace it on plasma and LCDs. It's still not here yet, IMHO. The methodology of using myriad combinations of video receivers and IR LED's (Wii, LCDTopGun, etc. ) seem to do ok, but it's still not on par with a real lightgun and a raster scanning screen.
The style of gun mentioned in this thread is pretty much a non-starter. The technology might have been ok as a pointer, with a cursor to follow and gauge movement with, but the attempt to apply it to a gun pretty much indicates a fundamental lack of understanding of the dynamic between gun and shooter. The "virtual bullets" flow down a tube, and therefore must strike the exact area of the screen where that tube would touch if it could be extended to the screen. Accurately capturing this angle with a single stationary camera is next to impossible, and even if multiple cameras were used, the results would likely be mediocre at best, and not worth the steps required to set up and calibrate such a system. The application of this technology to a gun is not so different from the way the "gyro" mouse devices were made to look like a gun. Yes, it might feel more like you are shooting, but in actuality, it's just a novel mouse pointer.
Gun mounted cameras are a much better solution, as pointing a camera and pointing a gun yield similar results. But the biggest challenge for this configuration is overcoming the disparity between the position of the real world markers (usually IR LED's, as they can be seen by the IR sensitive CCD, but are invisible to the human eye) and the on-screen target. In the arcade environment, things like marker placement in relation to the screen and shooter position tend to be tightly controlled. Therefore the system is "canned", and can, to a certain extent, make certain assumptions which provide for better accuracy. On a home setup, few assumptions can be made, as screen sizes, marker placement and shooter position all can vary to a pretty large extent. So the accuracy of these types of systems in a home environment rely on specific usage parameters and usually patented, or at least proprietary, calibration methodology based on specific marker patterns, etc... Unfortunately, deviation from the expected parameters usually results in a poorly performing or, in some cases, completely non-functional system.
The beauty of the old light guns is that all of the information which indicates where the gun is pointing is generated by the display. So the relationship with the screen is direct and requires far less extrapolation than other methods, which I am concerned will continue to be "hit and miss"

I have a couple of thoughts about how to re-establish this direct relationship between gun and target on new displays, but they would unfortunately require specific software and some fast display technology, so it's not much use for getting the old stuff to work.

This really rambled on, but hopefully parts of it will help folks understand some of the ways the different guns out there work and how to recognize the type of technology used. It might also give an idea as what to expect in the way of performance from the methods mentioned, but one should keep in mind that implementation reigns supreme. For instance, not all raster scanning compatible guns work as well as the GunCons, and so on.
RandyT