@Baldimo,
Really? A toddler? You keep guns away from toddlers --- period. Toddlers are not old enough to be shown how to handle a gun.
Do you also show a sharp knife to a toddler and explain the correct way of handling a knife --- no you keep sharp objects out of a toddler's reach. They are too young to fully understand this. Do you also show them how to handle matches? Or how to drive a car?
No toddlers are too young --- end of story.
I am not against explaining guns and the danger and seriousness of them --- but a toddler is too young to fully understand the true implications of them.
There is a reason you do not leave dangerous things out with a toddler no matter how many times you have explained the danger -- there was the temptation and they do not fully understand no matter how many times you tell them.
As far as explaining them to look both ways to cross the street - toddlers are too young for this as well. Yes, you teach them that....but then when they go outside and they see something across the street they want --- they just run. That is what toddlers do - just speak with my neighbor when I was a kid he thought the same thing until his 3 year old got hit by a car.
I agree you need to teach your children these things even at the age of 3, but that doesn't mean they are capable of handling this responsibility. Easy keep them locked and out of reach.