A Solothern S-18/100? (The one they work on during s2/e4 on Son's of Guns?)
Holy cow Lucchini! Are you trying to compete with Inagaki Mami for itty-bitty girl with the most firepower?!? (Mami used 2x40mm Bofors or an 88mmAT at different times in the Witches of Africa, and Strike Witches 1.5 books.)