Here is another controller that lets you get a more realistic VR shooting experience. The PPGun VR Bluetooth gun supports smartphones up to 6 inches, including iPhones and many Android devices. It has motors to provide you with vibration feedback.
The Bluetooth gun has customizable keys and lets you control up to 15 functions with a 5-output joystick. It also comes with a 9000 mAh battery. The gun weighs about 4lb.