I feel your pain. It took me DAYS to get it done. The fact that you lose progress upon death is the kicker. I don't do crucible much at all, and never use a hand cannon when I do. It was borderline unbearable. But, I stuck in there and got it done. Now, I am on the last part, which is to do the special Bond brothers mission. THAT is hard. I will tackle it again when I get to 295 light or so. Just hang in there and keep trying. Don't boost or cheat, you'll appreciate it more when you complete it legit.