18 years old is the age you need to be to own a handgun, long barreled rifle, or shotgun. That being said, you can only buy shotguns and rifles from shops at 18. The age you need to be to buy a handgun and handgun ammunition is 21. You can own a handgun at the age of 18, but you can't buy it from a shop. You would have to have someone older buy it for you or buy it privately. I turn 18 this week, so I've been doing some research and see where you're coming from!