"This is my Rifle, This is my Gun 20
Carried a UNSC weapon all the way through mission 3 on Heroic or harder."
the thing is, when you start the mission, you start off with an AR and pistol. However, after you board the pelican 1/3 in (and the parts with the Mantis), you start off with the AR and a DMR instead when you die.
I carried the pistol all the way for the first 1/3, and the DMR for the rest but it didn't pop. Has anyone done it with the AR?