It's been that way for quite a while. When I was AD in the early 80's we weren't allowed to carry on base. Privately owned weapons had to be stashed in the armory. There may have been an exclusion for those in base housing but I don't really remember.
http://ktar.com/6/1452937/Air-Force-Base-in-Tucson-on-lockdown ... eight paragraphs from bottom of article says shooter has been contained per several media outlets. Also says report unconfirmed. Any news?
If you live in government quarters on base with your family, you can have your private weapons in your quarters. You are usually required to registered each weapon with the MP station. We had a set of quarters broken into when I was at Fort Benning, GA back in late 1980s and the master sergeant who lived there had several thousand dollars worth of weapons stolen out of his quarters by local Columbus, GA gang bangers who came on base at night and drove around looking for places to break into. One night I was on the couch watching TV and there was a window in my quarters right next to the TV. Just an edge of the curtain was open and I saw an eye look into my living room right at me. I jumped up, grabbed my Glock and went out. The perp ran, jumped into a car with his gang lords from town and ran off. The quarters were located right next to a four lane high way that ran right through Fort Benning and it was easy for them to sprint right off base and be gone before anyone could get there. Now days of course, there are gates up and guards. But then, Benning was an open base and anyone could drive right onto the base.