If you can join the army at 18 and use a semi automatic firearm, you can own the same fire arm as a civilian if its available. The 2nd amendment right. The government should not be infringing on people's rights. Our they need to raise the minimum age to join the armed forces. If you consider 18yrs an adult and can make choices to fight for your country, they should be able to own a fire atm with proper background checks.