Comparison of 37-mm Ammunition from WW2 technical manual: TM 9-1901: Artillery Ammunition, War Department Technical Manual, June 1944:
FIXED AND SEMIFIXED ROUNDS AND SEPARATE-LOADING PROJECTILES: A – MK.II A1, PRACTICE ROUND FOR 37-MM GUN SUBCALIBER, M1916 B – M56 H.E ROUND FOR 37-MM GUNS, M4 AND M10 C – M56 H.E. ROUND FOR 37-MM GUNS, M1A2 AND M9 D – M63 H.E. ROUND FOR 37-MM GUNS M3, M3A1, M5, M5A1, AND M6 |