I ran across a decent scattering of people in the Marines who supported gun control. Not the majority, but since the military is somewhat representative of the larger population, there were a decent number.
Then again, even Marines, even in combat arms MOSs, don't necessarily have much "knowledge" besides the specifics of what they do. That is, they may be able to shoot and maintain an M16, and recite "The M16A2 rifle is an automatic, shoulder-fired, air-cooled 5.56mm weapon", but they don't necessarily know any more than that, or care to.
Though one of the more outspoken anti-gun Marines I knew was our battalion armorer. I dropped by the armory in Ramadi (Iraq) to drop off a bunch of gun magazines and catalogs I'd gotten in the mail, thinking the armorers might enjoy reading them during downtime, and he was very displeased about it. He basically said that Marines liking guns outside of work was unwholesome, and that only psychos and wannabes owned non-issue firearms.
He'd grown up in some rough neighborhood in L.A., and explained "I've seen what guns can do to a person." I found it rather odd that he basically implied that others didn't understand the dangers of weapons, yet all of us were in a warzone at the time, in a combat unit.
So there are definitely people in the military who work with firearms, and in some cases know them quite well, but are opposed to civilian ownership for political or cultural reasons.
Yikes! A 25mm handgun! Move over .500 S&W Magnum!
