If you live in the barracks you are required to keep your personnel firearms in the armory. You get a weapons card for it just like you do for your G.I. weapon. You are not allowed to have ammunition in your room or vehicle.
If you live in base housing you must register your weapons with the base Provost Marshall and you are supposed to keep the weapons and ammunition locked up separately.
You are not allowed a weapon in the cab of your vehicle. The exception is if you are going hunting and have a base permit to hunt.
I live in a state that allows you to keep a loaded weapon in your car. My wife is retired military and works on a military installation in a questionable part of town. I asked her to carry a weapon with her when she goes to and from work. She will not because she is not allowed to have it in her car on the installation.
Thousands of people come to work on various military installation everyday and you can bet most of them are not armed as they don't want to risk a career ending njp if they are caught with it. This creates a target rich enviorment for a terrorist. We need to change this.
As I said, the attitudes towards guns changes by location. And one last thing. The Military does not give a crap whether you have a ccw or not.
When my son was stationed at Ft. Bliss, TX, he was supposed to declare any weapons he had and he lived OFF post.