During the car chase scene, John is driving, John and Jane then switch positions in the van and Jane hands the black handgun off to John. While Jane is driving John is shooting at the BMW's with a black handgun. When Jane eventually destroys the Vans, she shoots the wheels also with a black handgun. If you go back though, while in the basement they pull out two guns, a black handgun, and a small silver handgun. Jane refers to the small silver as a girl gun so john gives her the black handgun.