Our children have seen our firearms, have looked through the sights on a rifle, see how bullets can go into and come out of the magazines, and have see mommy and daddy clean, prepare and holster their weapons.
What they are not allowed to do is touch them without first asking, then receiving permission, but only when daddy or mommy is right with them, guiding and helping them. There are serious consequences for disobeying any of the above.
We began by teaching our children the "Four Gun Laws." I have added a 5th, since it helps to drill the safety concept into small children. There are still grown people that I encounter who must be reminded of some of these from time to time, so make sure you know AND practice them! We will go over them further next time.
The 1st Law: The Gun is Always Loaded!
The Second Law: Never Point the Gun at Something You are Not Willing to Destroy!
The Third Law: Always Be Sure of Your Target and What is Behind It!
The Fourth Law: Keep Your Finger Off the Trigger Until Your Sights are On the Target!
(The Fifth Law: Do Not Touch a Gun Without a Responsible Adult!)