Great thread but there also needs to be a section for helpful kills like this one I posted earlier. It is accomplished in 7-4.
How to get 15 ultras in 1 minute on legendary.
"I would like to add to this that if you keep replaying the first minute of this mission and stay up top just snipe the ultras with your DMR that keep funneling through the door. I avoid everything but grunts while doing this and once they stop coming I restart the mission. You can get 15 ultras in 1 minute doing this along with a couple of jackals from all 3 classes. Also pick stickies as your gnade. Run up to the human nades right in front of you. From the top platform right as your hud pops up throw all 4 gnades at the front door at about a 45 degree angle. If done correctly you can kill a lot of the ranger jackals that like to jump up and kill you as you are doing this. Also put dexterity on for quick reloads there is an ammo crate to your right if you need some more and if you die just restart."