I thought it was in the scripting wizard, but since I don't have it where I am, I just came up with my own interpretation of how to do it.
As for slowing it down, no, it doesn't actually slow the game down, but it only shoots once every ten frames instead of once every frame with the way this works (because "delay" is increased once every frame, and if it's equal to ten, then shoot).
--Edit--
Oh, and to explain the OldActions And (Not NewActions) And ActionButton1, that's basically saying if they just stopped pressing the fire button. (ActionButton1 was part of OldActions, and Not part of NewActions)