Shop › MAGPUL AMAG 21 SG9 9MM SIG P320 SST MAGPUL AMAG 21 SG9 9MM SIG P320 SST $37.95 Magpul Industries Magazine, AMAG 21 SG9, 9MM, 21 Rounds, Fits Sig P320, Stainless Steel, Silver MAG1465-SST Quantity: Add To Cart Added! Magpul Industries Magazine, AMAG 21 SG9, 9MM, 21 Rounds, Fits Sig P320, Stainless Steel, Silver MAG1465-SST