Arilan Morrison Studio had its own shooting range, and if they were shooting handguns, there was an indoor range to choose from.
Jack brought out dozens of handguns, but sticking to the principle that the ammunition must be readily available, the caliber was limited to either 9mm or .45 ACP; all other various calibers were dismissed. After letting Gao Yang and the others choose their favorite handguns, Jack began observing their shooting.
The first handgun Gao Yang chose was a .45 ACP caliber M1911. After firing two magazines, Jack stopped Gao, picked out a 9mm caliber M1911 from a pile of guns, and waited until Gao had finished shooting another two magazines before signaling him to stop.