Reading your excellent piece in the Nation, How the Myth of the ‘Negro Cocaine Fiend’ Helped Shape American Drug Policy, these lines rang an old bell: 

Cocaine, in other words, made black men uniquely murderous and better marksmen. But that wasn’t all. It also produced “a resistance to the ‘knock down’ effects of fatal wounds. Bullets fired into vital parts that would drop a sane man in his tracks, fail to check the ‘fiend.’”

In the winter of 1963/’64 an NCO training us to use the .45 said the Army had to develop such a powerful pistol after a weaker one failed to drop charging Pilipino revolutionaries who were all hopped up on… I forget what drug. “We would shoot them and they would just keep charging with their machetes,” he explained.  I had a sense that the riff was from the standard  training manual, not his own personal commentary.