User blog comment:Callofduty4/callofduty.com updated with Ghosts teasers/@comment-10363123-20130519144751/@comment-1840877-20130522190738

Technically, we don't see the XM8 in BOII -- we see the M8A1. The key is the "A1", or "Advancement 1". In other words, in BOII's universe, the boffins found a way to build the XM8 without the barrel melting, so what we have is basically the "new, improved" model. If that makes any sense.