Are you assuming that management techniques should differ with armed employees because of the possibility of them going "postal"?
If so, the answer is no. I commanded the 3rd watch of a mid-sized city police department for around 6 years (retired August 29. Yeehaw!!
Cops can be a cynical, hard-nosed bunch to manage
Heyduke said respect. That's correct, but there's two kinds of respect. I can demand
that my officers respect my rank, but respect for me as a person has to be earned, and that ain't easy. It is, however, essential for a good supervisor.
A mediocre supervisor can throw orders right and left, and be a "my way or the highway" kind of guy, and get the job done, but he'll never get 100% from his people.
A good supervisor knows how to motivate his people, so that they want
to do the job, but that can only be done if they respect both the rank and
the person, and that can only be done if that respect is mutual.
To that end, I didn't micromanage them, and I believe in public praise, and private discipline. I showed them trust until or unless they proved they couldn't be trusted. And, I didn't sweat the small stuff. I cared.
The list goes on, but the bottom line is, a unit with pride and high morale is far less likely to have a "postal" incident than a unit commanded by someone that simply barks orders and doesn't give a hoot about his people, armed or not.