https://www.worldwar1postcards.com/3-the-flechette .php
"If one hits a man on the head it will go straight through his helmet into his brain." However, just as fatal was a hit on the shoulder by one of the steel arrows. The report continued, "it will probably glance off the shoulder blade and go straight through the lungs, and get mixed up with other parts of the anatomy."
Also how well did flechette bombs preform in ww1 cant find much on them