What I was thinking about doing was getting another upper for my AR in 7.62x39. I would like to have it barreled for .308 diameter instead of .310" so that I would have more bullets available for reloading. I figure I could get better accuracy and tougher bullets if I were to use the gun for deer. I would also like to be able to shoot the cheap surplus ammo for plinking and what not. Would shooting the surplus ammo be dangerous or cause damage to the gun? I thought I heard that it would not damage anything, but I wasn't sure. Is the scenario I am thinking about doable?