I could not resist. Here are the FREE CAD files for an AR-15 30 Round Magazine by http://defcad.org.
If you have a 3d printer and can follow the directions by http://defcad.org than you should be able to reproduce your own AR-15 30 Round Magazine Clips.
Grab your files today (so that you always have them), again they are free thanks to http://defcad.org (please support them, donation based).
Download Link –> ar-15_30_round_magazine_v2.0_defdist