I had a woodswalk one time where for one of the targets, a gong at 5 yards, I took a plastic coffee can lid, cut an X in the middle of it, and shooters had to put their barrel through the X so the lid blocked their view of front site, and pretty much the target. Really wasn't too hard to hit if you looked at the gong, lifted your gun, kept both eyes open and shot, but it really messed with most of the shooters.