I agree with Possum in so many ways. Although there are PT standards there are many, many soldiers that struggle to barely make the minimum standards, there are a horrendous number of soldiers, sailors, marines, airmen that cannot qualify on their rifles, handguns, etc all of the time. These things are skills taught and learned, if you dont expand, make use of, practice, you lose them. Its amazing how many non combat units let their soldiers get away without taking annual PT tests, and qualifying on the M-16, they pencil the qualification in.
I was stationed on a post that had division 4 mile runs which required by order of the post commander all units to participate, there was a 1 mile long group of stragglers mostly MPs, Pay and Finance, etc walking along the shoulder of the road miles behind their units. We had Brigade runs that were 6 miles long of which by order NO ONE WILL FALL OUT. Our Battalion 8 mile runs were the same way, you were dealt with by the old Sgt Major if you fell out, because he never fell out or slowed down from the front, we were Infantry.
The federal laws, and most state laws allow police/retired police to be either exempt from CCW requirements, or allow them to not have to take the classes for a Lethal Weapons Certification.
My weapons qualifications, and skills were something I was, and am very proud of, I try to keep them current and more than adequate in my mind.
The base commander makes the rules on post and off post when it comes to anyone stationed there. The military makes the rules on or off duty for all soldiers and how they live. Technically you can be court martialed for gettting tatoos if they choose to enforce the rules. A sunburn can be an article 15 if you got it off duty, destruction of Governement property.
Im sure carry of firearms off duty by soldiers, sailors, airmen, marines, is directly controlled by military law, if not by almost all if not all post commanders. Check the laws, and rules before assuming you can carry. After all you have no rights to sue, or go to court while in active duty.