Yup, here in Minnie have to be 18 to buy/own an AR as long as no pistol configuration, grips etc...and long guns, under age 13 for hunting etc under supervision...need to be 21 for pistol or CCW, but under 18 can handle under supervision...
WI & MN similar in most respects but WI less restrictive and I believe 14-17 can carry a rifle openly if a safety course completed...and I do not think they make distinctions on rifles like more restrictive Minnie does...