I have several steel plates I have shot with many different calibers. On a machine gun shoot we had Auto ARs shooting green tip penetrators, M-60 , sterlings, mp5 and a MacTac .50. That shoot employed 1/4" and 1/2" plates at 200yds. All the 308 went through the thinner plates and a lot went through the 1/2", of course the .50 cratered the plate and penetrated every shot. The 5.56 penetrator ammo has a tungsten core and NOT ONE penetrated. Granted we were at 200 yds. They did leave an interesting little scar at each of the several impacts. My 03 had no trouble punching through even a 3/4 bar.