From:
http://www.jouster.com/articles30m1/M16part2.html
"Hey Major" said the Gunner, "I've got something down here you need to see!"
"What's that Gunner," I replied.
"Major, we've got bullets sticking in the target faces!" said Luke.
"The hell you say Gunner?" sez I, "wait one, I'll be right there!"
I called a cease fire and headed for the butts in the safety vehicle. When I got there I could hardly believe my eyes! Sure enough, there were a number of projectiles that hadn't completely penetrated the multiple target faces at 500 yards. For a moment, I considered that the Gunner might just be pulling my chain, and inserting spent projectiles in the bullet holes for a joke. Two things changed my mind. First, while Dave Luke has a sense of humor, it doesn't run to things like that, and secondly all the projectiles stuck in the target faces showed no evidence of having struck anything more solid than a thick piece of paper. Not only that, but Dave was a professional range officer and we were conducting practice for a Battalion requalification program. Any undue delays would have reflected unfavorably on Dave's ability and he was not one to have allowed anything to interfere with his duties unless he considered it extremely important.