This is literally the third thread about dual wield handguns that I've seen in the last three days. Seriously, NO TO DW PISTOLS!
It's a stupid "HEY, THIS IS A COOL IDEA!!!!1!!one!" brain-fart that some idiotic people thought would make their game/movie cool. It's not cool. It's totally unrealistic. You cannot aim and fire two handguns at the same time with any kind of accuracy, at least with any speed. I saw a guy once shoot two targets at once with a pistol in each hand, but that was target shooting. It took him a good 30-45 seconds to line up the shot. In a firefight, you'd have been dead 10 times over.
PLEASE, people, no more DW pistol threads!