MOFF, for starters, eliminating all guns is an impossible task. (Okay, not impossible, just extremely unrealistic.)

Second, neither of the situations you list should ever have happened. You don't "screw around" with firearms, obviously the teens weren't mature enough to handle them if that is what they were doing, and a firearm should NEVER be where a baby can get it.

Firearms are tools, nothing more. Hammers, knives, axes, all have killing in their roots. A tool cannot be good or evil. It's the user which makes that choice.