reflection weakness 2

One of the armored men held out a handgun, but Kihara shook his head. The
countermeasure for Accelerator’s reflection could only be accomplished with a subtle
reversal of an arm or leg. It could not be replicated with a bullet.
And it was naturally only an attack method that was possible for that man who had
directly developed Accelerator’s powers. Even if others heard the explanation, they
could not pull off the split second timing needed.

- Toaru Majutsu no Index Volume 12, Chapter 5 Part 1