How do you get weapon attachments like acog and red dot for weapons online on battlefield bad company 2?

class unlocks...basically depending wheter you want it for a sniper or assault rifle just keep using the class and you eventually get the unlock which can be attached to any of the guns in tht class... e.g if you unlock 4x rifle scope for assault you can use that scope for any gun in that classHow do you get weapon attachments like acog and red dot for weapons online on battlefield bad company 2?
they are in the bonuses for your class. where the extra armor/ammo perks are. you might have to unlock them for your class.How do you get weapon attachments like acog and red dot for weapons online on battlefield bad company 2?
More kills in that class gives you attachments for all guns in the class. Or buy the cheat pack of the in game store