I imagine that machining cartridges for automatic weapons would be a pretty high priority, especially if it gave you tactical superiority. I agree that its easier to police brass on a range rather then in combat, BUT you make the point that all of the existing ammo would be used up already. If thats the case then there would literally be used brass everywhere. Also, I know a number of people who have the gear at home to reload and/or make their own ammo. The gear is out there and other tools like those in a high school metal shop could be adapted for it pretty easily. Why use "old" tech if you don't have too? Afghanistan is a fairly backward country to begin with. Its not like 1st World countries who would have advanced machinery and equipment lying around to be rediscovered or scavenged.