Since .30 carb and 6.5x55 are not commonly issued military calibers anymore, the odds of finding any pulled components are slim to none.
As for the .308: Ya know there is a war on, right? The US .gov is outsourcing ammo supply to whoever can provide, including Korea and Israel to get enough .308 as it is- the odds of having any "surplus" .308 are slim.
Believe me if I could find bulk .308 or 6.5x55 pulled projos in quantity I would want them myself.