I seriously doubt the capability of ANY pistol at 600 yds. This is considered a long shot even for the M-16. Even the Mark 23 Mod 0 Socom, which was designed from the ground up as an offensive weapon was only meant to be used at ranges of 50 yds or less.
Admittedly, since I am at work and without sound, I didn't watch the interview, but a 1911 at 600 yds? I want to know what cartridge is being used, cause it can't be a .45. I'm pretty sure at that range I could do more damage by throwing a round at you.