This still isn't allowing 16 year olds to buy guns. This would be stopping them from carrying or possibly even shooting one. The AR-15 is not a particularly dangerous weapon, it has a very small round and the magazine size isn't really a factor, it would be just as easy to carry a few extra smaller magazines with just as many rounds total. Where I'm from just about everyone has one and no one has gone on a shooting spree. Many teenagers use them because they're lightweight with little recoil, and can be good to learn to hunt or target shoot with.