Does anyone understand Halo 3 Ranks?

[Sam]

I've been playing ranked Team Slayer. It sais I'm a private. But when I play social It sais sergeant? Why is this and will my main rank always be sergeant unless I get it up or can I make my Global rank the same as my team slayer rank.
I know that Social gives you Army Ranks but not levels. And Ranked gives you levels and army ranks.. I don't understand why it shows my social instead of ranked though. Is it because my social is higher?

 

[squall]

in halo 3 there are ranked gametypes and socail gametypes, in social, u still get a military lvl but no skill lvl, in ranked you get both a skill lvl and a military lvl, silly randoms.