Contrary to what grizzly says, the Boomstick fires 4 times per reloading, until the final scene at S-Mart, where Ash fires it at least a couple dozen times nonstop.

Update: I realized that in the final scene, Ash is not firing his Boomstick, but rather a different rifle that he got from the display case. Regardless, he still fired the gun plenty of times without reloading.

Mentioned in other nodes, but should be here: Many of Ash's quotes from Army of Darkness found a new voice from the gaming generation. Around 99% of Duke Nukem's vocabulary can be heard in this movie, from "Groovy" to "Come get some." The term "Boomstick" has also found its place in gaming vocabulary, most often for the default shotgun weapon, but occasionally for rocket launchers as well.

Sasha Gabba Hey! says: In the BBC website, the science section has a rather nifty PC Theremin, which also comes with a few samples. One of them is the 'groovy' sound clip.