I really like your idea of aiming the gun into a mirror so you can see how they are aligning. I am somewhat afraid of your shotgun at a 2x4 demonstration. (I teach Hunter Ed as well to about 600 students per year). The reason I don't like the 2x4 is wood is tough enough to get some shot bounce back. We even had it come back and sting the shooter from accidental hits on wood of target table used to support a cabbage. We do that now with a sharpened wooden stake supporting the cabbage which minimizes opportunity for bounce back. I have become exceedingly cautious the last few years because of the number of incidents we have learned about from others and a few of our own incidents as well.
