If you’re intending to be a Halo 4 machinima creator, then you’d like a way to lower your weapon so it doesn’t look like you’re trying to blow someone’s head off all the time with your gun.
While it’s unfortunately not a simple button press like Halo 2 was, it is possible in Halo 4.
To lower your weapon, perform this four button combo: Hold jump (A), crouch (B), and reload (X) while pressing down on the D-Pad.
Yes, it’s not the simplest thing in the world, but it’s there. Hopefully you have a controller with a couple of programmable buttons.