In the US in general firearms are extremely common. I would guess it is part of our culture that dates back to normal citizens have firearms being able to overthrow an opressive government.
Where I come from hunting is huge, everyone has at least one rifle.
Just as a stat, America is by far the most heavily armed nation on the planet. On average there is something like 90 guns per 100 people.
The next closest is India with like 1.9 per ever 100 people.
So yes, guns are very common in the US, I know a guy that took his 3 year old hunting, I believe to teach her what guns are really for, and aren't toys. Again though where I come from hunting is very very common, and people don't get crazy with their firearms, they respect them for the most part.