Legendary? Hard? Try Mythic <________< .
I literally had to just sneak past everyone on certain part's because I kept running out of ammo. Legendary is decently tough solo, Espcially about midway through on Tsavo highway where about a dozen or two brutes get dropped off by the phantom. I spent so long trying to get past that section alone.
Good thing you aren't trying it solo though, I played some Co-Op legendary with a few friends the other day, It's really easy if you've got Co-Op going, but doing it solo will prove a problem if you aren't very good..
Good Luck and I hope you find a few to play with!
-Doom