(As found on Facebook)
While this debate isn't as old as the Caliber Wars, it has been fought with the same level of...let's call them apocryphal tales. Lucky Gunner has decided to bring some actual empirical testing to the subject, and sacrificed 4 AR-15s (or at least their barrels) and 40,000 rounds of 5.56 ammo to put the question to the test. The results are most interesting.
If you want to shoot steel case ammo and you're hoarding it for TEOTWAWKI, you might want to stock up on some spare barrels and extractors.