Twilight Gap, annoying fun tip, also useful for headshot spree bounty and getting heavy ammo.
Between A spawn and B there's a ledge. From that ledge you can see the heavy ammo drop near C. Easy sniping head shots every time heavy ammo spawn is coming as enemy gather around. Even if they get some, they'll drop a purple for you if you kill them just after. Timing of the drops is every 3 minutes.