Ramline used to make a 25 round mag,but are no longer made.Maybe try ebay or gunbroker.com,but be prepared to pay $$$. I only know of several companies putting out 8 round mags. I saw somewhere a few years ago someone had welded 2 stock mags,but don't remember if it worked. Also there was a clamp that would cinch 2 mags together.
AR7 Mags?
