I would guess that the higher the caliber semi-automatic the safer for the kids.

I would have my doubts that any kid under 8 could chamber a round in a 9MM glock yet a 22 could be operated by virtually any child. Revolvers are a definite no no keep them secured.

As far as displaying the weapon, well if the statistics are right. then 2.5 million guns are shown every year in defensive situations. Of that 2.5 million only a few ever result in the next ligical step.

Keep a 12 gauge pump in the house unloaded and don't own any ammo and most criminals will run at the sound