can have a man hold up a 12"x 24" cardboard torso of a man, over his head, on a 2x2 post, hunk of conduit, pvc pipe, etc. Then, have him dodge, holding the target,as he would if he were being shot at. fire 20 rds in say, 30 seconds, at 200m, and SEE how many hits you DONT get.
Every 3-4 seconds, he is to pull the target down out of sight, and then pop up again, 2-3 seconds later, at a DIFFERENT place. Then have him put a 6"x6" "head" on the pvc pipe, etc, and hold it exposed to your fire for say, 1-2 seconds, and then pull it down again. While this is happening, have somebody whipping your shoulders with a flyswatter, and tossing rice on your head and shoulders. this is a close simulation of havind debris thown at your face, by near misses of the enemy's rifle bullets. Do all this without ANY ear protection, of course. Then you will have a REALISTIC expectation of how LITTLE hitting you are going to do, even in DAYLIGHT of a charging group of riflemen.
If you REALLY want to know how BAD off a fixed defensive position will be, try the same thing, at HALF the range, at night, by flarelight.