Ok so with this bug I’ve noticed (but no bug report I’ve found addressing it), Someone can simply bind their shoot key to mousewheel down or up, Equip the Br-16 or Stark AR and just flick the wheel up and down, and the burst fire rifle will shoot fully automatically (or at least way faster than it should).
Have I personally done this glitch? no, but I have seen a video on it which is linked below, It’s easier to notice how consistently and rapidly the ammo counter goes down with almost no pauses rather than looking at the weapon animation
Video (Not mine):