The ammunition problems with the M-193 was thanks to McNamara and his pencil pushers. He wanted more ammo made per hour and the only way to do that was adding new machines or speeding up production with the machines that were in use at the time and they were running at 8000 rounds an hour as it was. So they go to Winchester and instruct them to make a ball powder for the M-193 round as that powder would help increase production. Winchester stated that they had one powder that was being experimented with. The pencil pushers grabbed onto that and insisted Winchester make it and use it in production. Winchester said no that the powder was not ready to be made and used and stated such in a letter to McNamara. They told Winchester to make it or loose all contracts with the government. So after they again stated a protest they made the powder. Calcium carbonate was the culprit. That was used to neutralize the acid used in production. It become part of the powder as it could not be washed out of it. So when the troops got it and fired it the carbonate coated the bores and chambers of the rifles. Many troops died because of this and as Winchester said later the only way to remove it was to use an acid and to do that was to destroy the rifle. Cleaning was useless as it would not work. This led to the chrome lined bores in the M16icon even though the powder was no longer used. Just another example of politics running a war and not the military.