Why is my Halo 3 BR/Sniper off from game to game...?

[iDare]

sometimes I play halo 3 and my BR/Sniper is on one game and then in the next my BR/Sniper is off.
I dont get why this happens some games...

 

[Timmy]

number one it might be u lagging or the other ppl lagging so check ur connection plus there are ppl that have lag switches that they can turn on and off when they want....
second idea kick back
third idea ur a crappy aim........