If this one doesn't glitch for you, as it did not for me:
In the mission Hypocenter, at the point where you have to disconnect the server system, there are 3 grenades that need to be placed into it. Go ahead and do the first two. At this point there is an infinite respawner for exploding robots. Just run backwards in a circle around the edge of the server system and just kill them all, they drop very easily. They also seem to drop ammo (I was using the Kuda) and there is also an ammo box here. I went into the level with 275 kills on the Kuda and it stormed up to 650 in no time.
Hope this helps someone who was also as unlucky as me not to get the glitch!