Two Russian firms, PMG LLC and PROline, have developed a 10 round drum magazine1 for the Saiga-12 shotgun. The SD-10 looks pretty nifty. It is slightly shorter than than standard 5 round magazine while holding twice the capacity. The final product will be made of black high-strength polyamide with a translucent polycarbonate back.
The manufacturer is currently looking for US importers ( Their email: PMG-LLC [at] Yаndex [dot] ru )
These type of magazines are commonly called drum magazines, but rotary magazine would be a more correct term. A Ruger 10/22 magazine is a rotary magazine, while a Thompson drum magazine is a drum magazine. ↩