I've noticed that sometimes when I fire the sleeper nothing leaves the barrel, even though it uses one shot up nothing leaves the barrel, I know because I'll be aiming down the sights and fire at a group of enemies (red bars) and they take no damage, and I don't see a laser. Also I find the ricochet is just for show as it doesn't hit more than one enemy. The perk says that the laser tears through enemies but when I line the thralls up in the sunless cell, it ricochets off the first one and off into the distance, never to be seen again.