My 4 year old is way too young yet, but he has the interest.
He has exactly 1 toy gun , which is actually a plastic flintlock pistol from an old costume, which I use to help demonstrate safe firearms handling (though he also knows what to do if he sees a REAL gun - he knows what we are learning is for when he is a "big" boy)
However it is pretty funny, the other day he was playing with the gun, he had a cloth and a little empty bottle, I asked what he was doing .. he said he was cleaning his gun
The wife is more than a little hesitant to let him start shooting too young, so probably the .22 will have to wait til cub scouts.
A pellet rifle though.. hmm ..
well obviously I am going to keep my eye on this thread for good pointers.