30-06 Question

[jmoore]

According to History of Modern U.S. Military Small Arms Ammunition, Vol. II 1940-1945,
the only changes to M2 AP in that time frame would have been a change away from the 4% "WD-74100" tungsten steel core to manganese molybdenum or high carbon steel at lot #FA 473 in Feb. 1942 and a run of gilding metal clad steel jacketed AP that started mid '42.


The AP did increase throat erosion according to Aberdeen testing, initially reported as 32% faster, but later revised downward (the book doesn't seem to have the later numbers). Perhaps this testing led to the revision? Not sure what reference was used, footnote lists OCM26376, July 29,1943, but I think it's in relation to accuracy tests mentioned later in the paragraph on pg.74.




M2 Ball ammo saw full scale production of gilding metal clad steel jacketed bullets commence in Sept. 1942.


Not seeing much else that would be a prime reason to change the rifling origin area. Could have been done for other reasons. Ease of manufacturing, reduced rejects, longer accuracy life, better accuracy, which would have been discovered during testing along the way. Perhaps a normal gov't delay in the transition away from M1 Ball?