They make them for several guns. I have two for my HK91's. They are quite good. Not bulky and length is good. Heavy when loaded. But 50 is much better than 20 when firing full auto bursts. I'll post pictures next time I take them to the range. Expensive at $250 each.

Good people sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf.

Someday your life will flash in front of your eyes. Make sure it is worth watching.