Teens with guns

I going to make a couple of loosely related observations about schoolyard snipers. Many advocates of "sensible gun control" seem to think we need to keep guns out of the hands of teenagers, or at the very least, military grade weapons. 

1. Some people think the solution, or at least one solution, is to have police officers permanently stationed in public schools. In that regard I'd simply point out that many many teenage boys can easily subdue and disarm a policewoman. I don't mean if her gun is drawn. I mean in the more casual atmosphere of a high school, where police officers wouldn't maintain the same physical distance or be on guard in the same way if they were walking the beat and interacting with strangers (which they usually do in pairs). They see these students everyday. 

A boy who had designs on shooting his classmates wouldn't have to smuggle a gun through metal detectors. There'd already be police firearms on site. The policewoman would be the armory. So long as he had the ability to overpower her and take her gun away, that's all he needs. 

2. Teenagers regularly enlist in the military. You can volunteer at 18, or join at 17 with parental permission. I don't have these statistics at my fingertips, but just since the advent of the all-voluntary military, we've probably had hundreds of thousands of teenagers (junior NCOs) with access to military grade weaponry. And that's not counting teenage draftees during WWII, Korea, and Vietnam. I'm guessing we've had millions of teenagers with access to military grade weaponry over the decades. How many of them have perpetrated domestic mass shootings? Surely the percentage is infinitesimal. Likewise, you can go straight from high school to police academy, which gives cadets access to police firearms.