Well, I posted last month that the Marine Corps would be fielding the 'new' SOST heavy-hitting rounds in Afghanistan this past month. Well... they have been using those, and with good success (from what I understand). But now hear this: now there are talks of stepping it up to 6.8mm rounds... here is the article in the Marine Corps Times:
General Mattis about 6.8mm Rounds
General Mattis about 6.8mm Rounds