This is because Olin remanufactured old powder into the "new" ball powder to supply to the government - which has a calcium content in it.
Small but magnum-loaded, the round is one of the most cantankerous in the history of American small-arms. Since 1964, when the Army was informed that Du Pont could not mass-produce the nitrocellulose-based powder within the specifications demanded by the M16, Olin Mathieson Company has supplied most ammunition for the rifle with a high-performance ball propellant of nitrocellulose and nitroglycerine.
Known as Olin WC 846, the new powder is capable of firing an M-16 round at the desired 3,300 ft. per sec. and has unexpectedly increased the rifle's automatic rate of fire from about 850 shots a minute to 1,000. The result is that the "little black rifle," as the M-16 is fearfully called by the Viet Cong, tends to jam because the powder leaves behind a dirty residue that clogs the faster-moving automatic parts.
-Time Magazine, Friday, Sep. 08, 1967


















































