It is my understanding that an off duty police officer ran out of ammunition during an active killer incident a few years ago in Salt Lake City. The story is that he was celebrating Valentines Day with his wife at a mall in down town Salt Lake. The shooter was armed with a pump action shot gun and started shooting on a lower level of the mall than the off duty officer. The officer engaged the shooter from a higher position, did not hit him, but did contain him until on duty officers arrived and finished the fight. The off duty guy was reportedly armed with a 1911 with one magazine and had expended all of his ammunition.