That type of gun is called a "rifle", and it's typically considered most effective at distances greater than ~3 feet. Any closer and you might need to step back to avoid smacking the target with the barrel.

Guns don't really have "effective ranges" like is often portrayed. Close range guns are usually close range because they're physically larger, not because of the movement of the bullet. A gun you need to point upwards to carry up stairs is not as good if you might need to fight on stairs. Likewise, if someone is close enough to grab the barrel you probably want a weapon that they can't do that to.
Weapons with longer barrels can often accelerate a bullet longer, giving it more power and accuracy. That's why they tend to be viewed as distance weapons.