To conduct a metallurgical examination of the subject projectiles and to evaluate their design, manufacture, and performance characteristics. Complete engineering drawings were made of each projectile after which they were subjected to metallurgical examination including chemical analyses, hardness surveys, and macroscopic and microscopic examination of all components. The bodies of the shot were made from me - dium carbon manganese silicon-chromium steel. The 45MM and 85MM shot were machined from barstock while the ogive of the 57MM shot was hot formed. The 45MM and 57MM shot were uniformly heat treated to a hardness of approximately Rockwell C 50-55 while the 85MM shot was decrementally hardened from Rockwell C 46-50 a t the nose to Rockwell C 25 a t the base. All shot bodies were deeply notched circumferentially above o r below the bourrelet, the two smaller caliber shot with two notches and the 85MM shot with one notch. The nose of the 45MM shot was flat with slightly rounded edges, that of the 57MM shot was knob shaped while the 85MM shot had a conventional ogival nose. The 45MM and 57MM shot were fitted with deep drawn low carbon steel ogival windshields which were crimped into grooves knurled into the forward end of the shot. The 45MM shot was fitted with a single copper rotating band and the 57MM and 85MM shot with double copper rotating bands. All band seats were undercut from 15O to 20 .
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