I've been hand loading for 40 years, and I load for over 35 cartridges (at last count). Only twice have I ever had a primer go off (I'm talking tens of thousands of rounds). I've crushed them sideways, upside down, every which way over the years. That anvil has to be "smacked" just right. As others have said, SOMETHING hit that primer. Did the kid drop something on top of the box of S&B ammo while it was on the counter? Oh, I also work at a busy gun shop and i'm throwing around cases of ammo, handling boxes of ammo, and sometimes loose ammo, all day long, NEVER had a round go off.
