Halo 3 UNSC spartan question??

[Adam B]

I just hit seargent on my overall rank in halo 3. When this happens your supposed to get an achievement called "UNSC Spartan" and you unlock the Mark V helmet. Neither of these things happend for me. Anyone know whats goin on?

 

[tell ya l]

I believe you are suppose to get a certain amount of EXP. before it happens!

 

[tell ya l]

I believe you are suppose to get a certain amount of EXP. before it happens!