Against a person-sized target, if its user is a decent shot, your average modern handgun is accurate to about twenty-five meters. Voldemort probably isn't that far away, and I'd expect him to know what he's doing. He's shooting one-handed, and left-handed at that, but I wouldn't rely on that.

On the other hand, when he was laying out his plan, he was going to have one of his mooks shoot Harry. That's unlike him, and it might point to him still being bound by his Riddle curse, or to enough caution over unintended consequences to take the gun out of play for the moment.