One can get a headache listening to politicians misuse the terms "magazine and clip" interchangeably. Here is a simple definition:
This is most likely what they're talking about. A magazine is a box (tubular, drum, or rotary configuration) that holds bullets or shells under spring pressure and readies them to go into the chamber of the gun. The spring pushes a new round into the chamber after the previous casing has been ejected.
are different. Odds are, an average shooter has never fired a weapon that uses one. The clip has no spring and only holds bullets in an orderly way as they are fed into a magazine within the mechanism of the gun, the gun then moves them into the chamber. When the clip is empty it is ejected. It is called a clip because the bullet is held by strong immovable clips.
The M1 Garand uses a clip, and the M1A uses a magazine. If you have the chance, we recommend using the rifles to see the difference between a clip and a magazine. Each are a joy to shoot and full of history, it is worth your time.
Most other modern guns use magazines. For your gun, you must always use the right size.
Purchase the quality you will need for the level of shooting you will be doing:
A cheaper aftermarket mag will serve for heavy practice use and you won't feel bad when you throw it in the trash if it doesn't feed well, or the spring breaks.
But, if you want a works-every-time mag for a home defense gun, always use the one made for your gun by your gun's manufacturer.