There is no such thing as a "30 round clip". They don't exist. Clips, aka stripper clips, are small strips of metal that organize ammunition so that it can be more easily fed into "old style" internal magazines for rifles like the WWII model M1 Garand, or the Mosin Nagant rifle that originated in the 1800's. They come in 8-10 rounds units, not 30.
Removable magazines on the other hand, like those used by the AR-15, do come in 30 rounds.
Magazines. Not clips.