in one of the final trailers before avp was released there's a part where it shows a predator holding a stuggling alien and unsheathing his wristblades. After that shot you hear a motion tracker.
at this point it cuts to three marines (c-block backdrop), the Rookie in the center,a marine with a pulse rifle and a marine with a heavy weapon on a gyroscopic harness. They pull their weapons up and start walking towards the camera.
Upon closer inspection,the heavy weapon the marine on left is holding looks to be a minigun (Since it's multi-barreled). it's been verified as something removed from the final game by S.Y.L. on here.I'm thinking it was the original design for the newer model smartgun in the game.