Standard nomenclature lists. F-22. Telescope, panoramic, M2 (mils); M2A1 (degrees); M2A1 (mils); M3 (degrees); M3A1 (degrees); M4 (mils); M5 (mils); M5A2 (mils); M5A3; M5A4; M5A5; M5A6: M6 (mils); M1917M1 (mils), addendum; Aug. 18, 1943.