Using Onager early

hgaV6o0iZLM On the level The Pillar of Autumn in Halo: Reach, it is possible to board and fire the Onager before you are supposed to. In order to perform the glitch, you must have a concussion rifle and a drop shield, and have the Tilt skull enabled.

First, stand on the railing of a small set of stairs leading down to the landing pad at the very beginning of the section Keyes. There should be a pipe to the top right, above you. Use the concussion rifle to launch yourself up by shooting at your feet, and land on the pipe. Then, launch yourself up again to the platform with the MAC gun. You can now operate and fire the MAC gun as normal and use it to shoot down the various Banshees and Phantoms flying around.

You can also get to the Onager by jumping on a Phantom as it leaves after droping troops, and using Armor Lock as you hit the death barriers. You will then jump off to the rocks above and make your way down to the gun.