You might not get access to the Halo 4 until it is released for retail sale, but you can have a vive of it. A new screenshot from Halo 4's multiplayer leaked onto the internet which gets you a close look at the gameplay interface.
The image usual Halo background with M274 Ultra-Light All-Terrain Vehicle, or better known as the "Mongoose" and an intriguing ARC-920 Railgun on the foreground.
The ARC-920 Railgun is a "compact-channel linear accelerator that fires a high-explosive round at incredible speed, delivering both kinetic and explosive force to hard and soft targets alike".
The Railgun doesn't have a zoom function. And while the Railgun doesn't do as much damage to vehicles as the Laser, it does have the potential to change a vehicle's force and direction with a well-placed shot.