In Halo 3 videos, how do they do that?

[Halo_odst_=D]

In youtube videos of Halo 3 they can lower their gun instead of having it up. Like in "Arby n' the Chief".
I would like to do that. Do u have to have a mod?

 

[Aaron]

No mods, All you have to do is sit around for a while and they will put down there guns plus there skilled lol

 

[G.I.P Blue]

http://www.machinima.com/forums/viewtopic.php?t=9083

You could just have googled it, Google is your friend :]