"Hands and arms can be the fastest-moving body parts. For example, an average suspect can move his hand and forearm across his body to a 90-degree angle in 12/100 of a second. He can move his hand from his hip to shoulder height in 18/100 of a second. The average officer pulling the trigger as fast as he can on a Glock, one of the fastest- cycling semi-autos, requires 1/4 second to discharge each round. There is no way an officer can react, track, shoot and reliably hit a threatening suspect's forearm or a weapon in a suspect's hand in the time spans involved."