the ranking system is so screwed up at the moment:
Yesterday my rank bar was at 100% for 2-3 hours and nothing happened. Today: Everytime I log in and start to play on a map I get promoted to Private First Class. The stats do not show it. Every time I log out the promotion is gone next time. But when I get the first kill it's back.. but still doesn't show in BFHQ.
Maybe they will reset all that stuff in the next days ... so everyone has to start from scratch again...