Does anyone here have and use these training aids any longer? A friend of mine lost his on tour years ago and was recently telling me about this sight training tool. He did rifle training while in the Navy. I assume it was proprietary to a narrow rifle setup..But, if something like this could be calibrated across the board-I'd buy it!! It would be useful for both the student and the instructor real time. I'd like to hear more about these things. Thanks.