I talked with my friend and he said that those cases are "cold headed". That is, formed cold under great pressure with a die, so that there is no material waste. He said if he were to machine them the material cost alone would be from $2-$3 each. Before any machining was done. He seemed to think it cost prohibitive. If you're still interested I'll talk to him some more about it.

Stan

May God bless America and those who defend her.