Only if you are a felon...(None in the United States).
Federal law is 18 for long guns and 21 for hand guns.
No exact answer, as there is no exact record- a good estimate is about 120 million privately owned handguns in the US.
hand guns , long guns, Air guns , Rifle these are used as a firearms .
Long guns and hand guns.
Long guns and hand guns
Hand guns and long guns.
hand guns, long guns, blackpowder
21 for Hand Guns. 18 for Long guns.
Two: Hand guns and Long guns
Long guns and hand guns.
Only two; hand guns and long guns.
Hand guns and long guns, cannons