Guns won't fire automatically XBOX 360

Whenever I shoot my gun or the gun in any vehicle, regardless of being set to automatic, they refuse to. My guns will shoot in bursts, single fire and random amounts whenever I hold down my trigger. I'm even firing helicopter guns in burst rounds while the trigger is firmly held. Are there any solutions to this? I'm sick of having to tap fire in every single encounter and I'm sick of dying in CQ because my brain defaults to try and fire full auto