The episode of Numb3rs that aired April, 28th, 2006 - In the start of the episode a guy takes a hostage and fires a total of 18 bullets from his gun. It appeared to be a Glock, I know of one model that has a 17 round clip, and if another was chambered that would explain it fine - however the police themselves said he "emptied 15 rounds" clearly for a show based around some math genius it would have made sense for them to get the count right!