On halo 3 ive earned the Spartan Officer Medal but no achievement?

[LooksLikeUJustGotPwned]

I didnt recieve an achievement or a helmet for it!

 

[Carly B]

I'd say just let the game do what it's supposed to do. It knows what it's doing, unless there's a glitch or a big scratch. I play that game all the time. Totally fun.