From what I've heard you're chances of getting a CHP in MD are slim.
As for arming the military 24/7. The military is not unique in being a target of terrorists. By definition the citizens are the ones the terrorists want to hit, that's how terrorism works. If they hit a military base in MD the populous will go hmmm, well they hit a military target so I'm cool. If they hit they local bus terminal, that causes terror.
I was in a military unit authorized concealed carry 24/7 everywhere it went. It was interesting that no real specific training was provided. That unit got a hard look when a couple members were off duty and foiled a robbery at a store. Not what the concealed carry was for and it got them exposure they didn't want or need. No they weren't in danger of being killed or harmed, they decided to stop the robbery ie. playing cop. So the concealed carry permission was dropped.
There are units that have concealed carry authorized, but they are few and typically are trained for concealed carry. I don't think the military wants to deal with the liability and training issues that would arise from arming all their personnel 24/7. I don't think the states would accept it on that scale either.