Have never heard of an underwater assault rifle. In the US, you must be 18 to buy a rifle, and 21 to buy a fully automatic rifle.
18 to buy a rifle or shotgun, 21 to buy a handgun or assault rifle.
18 for a military style semi automatic. For a true assault rifle, which would be an NFA Class III full auto weapon, 21.
No
An 18 year-old can buy a Title I long gun, which includes semi-automatic rifles. For a true, full auto assault rifle, which is restricted under the National Firearms Act and first requires approval for a Class III tax stamp to purchase, you must be 21, as per federal law.
In MOST states it is 18 to own any shoulder-fired weapon. In order to own what the military considers an assault rifle, you also have to have a Class 3 Federal Firearms Lisence, but some states and cities definition of an 'assault rifle' includes anything that looks dangerous and NO ONE is allowed to own one there.
Medal of Honor European Assault is rated teen so you can buy it.
18
18
18 for long guns like rifles and shotguns, 21 for handguns. The so called "assault rifles" are just really semi automatic rifles that look like military guns.To own an NFA firearm, such as a short barreled rifle or shotgun, or a true assault rifle with the selective fire functions, the minimum age is also 21.
18 in the US
18