Me and Unstable Fox found this method, feel free to make a video on it but please credit us (Instructions below)
There's also 2 methods to get this glitch to work, the other method was by Unstable Fox and will be linked below
Full instructions (MUST BE CO-OP)
1: Have the host start the "Treasure Hunt" Challenge
2: Wait for the timer to say "Go!" and spam down on the D-pad until the fast travel option comes up
3: Once it comes up stop spamming the D-pad down button until it disappears
4: Hold D-pad down again straight away after it disappears until you get teleported to the host
5: Go out of the GRE Container and look at the closest windmill and hold Square/The equivalent to that to open the map
6: Go to your player item menu and drop the quads damage's they're unlimited so you can drop as many as you want
7: After the challenge fails (either die or run out of the mission are for over 10 seconds) go to where you dropped them and pick them up
*The other method*
Go check out Unstable Fox's video: • How to get 1000 shot quad damage in D...