This gun just won't drop for me. Nothing i do is apparently good enough for it to drop. I set my modifiers so that my score was forecast as A. I struggled through and finished with 26:34 left before the timer ran out. Then for some reason it gave me a B+. No Choir of One drop still. The exotics missions need fixing. The exotic should drop on first completion. Always. The catalysts should be tied to the chests and puzzles. The only thing score should affect is the portal gear drops.