The famous DLC2 mission 8 for weapon farming.
Thanks to RudolphRandolphRübenrunkler for the tactics ( • EDF Earth Defense Forc... ) .
My Blast Twin Speer M5 are near fully upgraded (only 7 stars in attack).
As you can see it is doable with quite low armor (4334).
As for the tactics: fight on the big beach and try to round up the spiders by turning around them. Go for the ones on the outside of the herd. You shouldn't take massive damage. If you do, turn larger and go for the white/yellow crates.
EDF!