I never knew that! You learn something new everyday.
The military probably passed on it due to the longevity of plastic. In other words ... a brass case will sit in the ground for 100 - 150 years
maximum before being turned back to it's original elements.
A plastic case however ... that's an
indefinite amount of time in the ground. Probably close to 400 or 500 years before it is completely broken down. Who knows with that polymer composition. Maybe closer to 1000 years!
Can you imagine ... 500 years from now, and the only thing left of our civilization is plastic?
That will be our legacy!
Then there is the whole dependency on oil thing .... plastic is made from oil. If we are fighting over oil in the future ... we would have to revert to brass for our ammo casings if they went with the plastic.
Then ... ATK / Olin would be out of business .... 300,000 people laid off because of the loss of the military contract ... it's all economics with the government. That's their bottom line. What is the bottom figure ? I'm not speculating ... only stating facts. You have to consider ALL of the ramifications of such a revolutionary idea.