Except the ones that didn't.
Seriously. You can't believe there was never a gun-related accident before the 21st century, can you?
You might not have heard about those fatalities as much, probably because we either weren't born yet or were paying more attention to Sesame Street than the 6 o'clock news, but they happened.
And they still happen now. I won't post a link because, you know, politics, but over at the DailyKos website, they have a weekly compilation of "GunFails" in the US. Many of those GunFails come from legally owned guns from supposedly responsible gun owners who, for a moment, were not. Some of those gunfails are injuries or fatalities from the gun owners ironically in the process of showing others how to fire or care for a weapons. And sadly there are almost always instances of children getting access to a gun and either playing with them or trying to use them to intimidate someone else without really udnerstanding the consequences of their actions and firing.
Mind you, the gunfail column is not a column where every shot fired in the nation is documented. They don't bother with the times when, say a cop was being fired upon by a criminal and responds in kind...unless he winds up shooting an innocent victim along the way. These are just most of the whoopsy-daisies that happen in the course of ay given week in America.