What's the 'age factor' in becoming a soldier? If you knew what kind of people can manage to get hired into local Mayberry PD's it would make your hair stand on end---but then the same could be said for the Army.
True. But, the Army and the Marines do have a vetting process which does eliminate most of the undesirables before they are loosed upon the battle field. Unfortunately, that does not always work and some who become unhinged give the rest a bad and undeserved rep. Of coures, the battle field is a completely different world than one’s own neighborhood here in the U.S. (with the exception of certain areas of the country of course).
Yeh, but the military has a couple of chances to weed 'em out. Basic and AIT (or whatever post Basic training is called in a particular service. Then then don't really trust 'em for a while, sometimes forever. For a good while, their NCOs watch 'em like hawks, sometimes apparently not too friendly hawks at that. (Appearances can be deceiving of course).
Guns are highly controlled on any military base. Basically except when on the range or in the field, no guns are allowed. Guns not in use are kept in a unit armory, not in the individual's quarters, be that a barracks, or on post housing. Although I have seen troops who were getting ready to be deployed carrying their individual weapons with them all day long, even in the mess hall, but they had no magazines, loaded or otherwise.
FWIW, the NCOs also watch the LTs, as do the Captains, Majors, etc. An LT can be a very dangerous creature. I should know too, I was one once, although in blue not green. And our (very technical) outfit didn't have enough Chiefs to raise us properly.