The thing about most guns is that they kick, something especially true of shotguns and automatic weapons. When the firearm discharges, the explosion in the chamber and subsequent chain of events and physics to send the bullet or shot at, say, 1,200 feet per second or faster, causes the barrel to rise. In the case of a shotgun, it also sends the stock back against the shooter — in some cases hard enough to knock him down.
I learned this as a child in the West. I learned it the right way, with competent, demanding adults and on properly prepared and supervised ranges.
For example, the first time I ever fired an automatic rifle was when I was nine years old. Yes, the same age as the girl who accidentally killed her "instructor" at an Arizona "shooting range" when an Uzi kicked up and out of control.
In my case, some essentials were different. For example, I had been taught basic gun-handling at an early age. Never take a firearm without making sure it is unloaded; with an automatic or semi-auto, that means not just dropping the magazine (not a "clip" unless it's an M-1 rifle) but also clearing the chamber. Never point a gun at someone "unless you intend to shoot them," said my mother the crack shot. Never traverse a barrel in someone's direction as you are handling the weapon. Even if you know the gun is unloaded. You always "police your brass" after shooting.