Clips go in an M1. Magazines go into an M16A2.
Either way, you put the little boomy things into the big stick that make them go boom. And either way, the end result is a boom, regardless of what you call it. Unless you arent taking good care of your weapon, in which case the end result may only be a click. Which is sad, because boom is much more fun.
I like things that go boom.