Minot AFB is currently using Army reserves as supplimental guards. Of course, being a nuke base leads to different security requirements. They get all the toys... I just love the idea of a full-auto grenade launcher.
Back before 9/11, I was stationed in colorado springs, and Fort Carson had NO gate security. All the AFB's had gate guards at all times, but you could just drive onto the fort. That's probably changed now, but I remember it being weird to me even back then. Every installation I'd entered before then had guards at the gate. Of course, I hadn't been to many bases at that point.
When I was in Europe, I was selected to be an auxillery for a while. I've heard about them not issuing ammo, but this was after the Cole bombing and 9/11, and every time they gave me a weapon, there was a loaded magazine in it, and I had spares. Even during exercises. Made exercises interesting, when everybody is running around with loaded weapons...