Wouldn't this make any commets invalid then since we are all commenting on old designs?
Whats your video CRT?
If your using a TV or arcade CRT consider going with the gun2con and the driver (search for the giant thread here). Its the best and cheapest solution... plus you can get guns that look like guns. Trouble is they don't have a VGA board thats verifiable.... lots have almost got it working I guess but not confirmation without issues (like some resolutions don't work).
Next... VGA... Then act labs is probably the best solution. Good gun. Feel cheap. Trigger on new models break. Not arcade worthy in any way. It will be the cheapest item on you machine. But its still the best solution out there. Getting two guns to work together requires analog+ mame (with core powers

) or old nonamemame version.