What is the risk of a factory round being overcharged? Bad powder lots happen, but again, it would have been a major issue with recalls, etc.
Think of all the safety checks that a typical handloader is SUPPOSED to do during the process. Multiply that by about 50, for a company with all that liability on their shoulders. With their setups, they can probably tell if one round is off as little as 1 grain of powder.
I guess anything is possible, but one cartridge out of a box is going to be in the same ammo run as the other 19. Something is very odd.
