Magazines!...I also keep a couple of clips close by.
A clip is used to reload a magazine, either attached or internal, think your Garand or the 1903 Springfield, 1898 Mauser Karabiner, the such.
A magazine is the device that physically holds and stores the ammunition.
Look at it this way: a Clip feeds the magazine, the magazine feeds the weapon. The interchangeability of incorrect terms drives me insane, haha