The 9mm Hi-Power (King of Nines) was a pistol designed by John Moses Browning. This pistol was noted for having a double-column magazine of 9mm rounds[?], capable of holding 13 bullets (a 14th was often inserted into the chamber[?]).
... one end of the axis to push against the upper rim of the groove, while the other end of the axis pushes against the lower rim of the groove. While the axis is slipping ...