I think that is irresponsible to bundle "possession" and "use." Much of rural America still practices the sport of hunting. Many forms of big-game hunting require the use of high-powered rifles that are also considered assault weapons. Regardless of whether not you support hunting, it is an important part of American culture, both recreationally and for the for the sake of acquiring organic meat that is otherwise unavailable (yes, people still do that). I personally do not think that a minor of 16 should be allowed to possess (own) an assault weapon but they should not be prohibited from using one legally possessed by an adult.