Well I just bought the taken king yesterday, and I did some missions, then I went back to the tower to look around at the new stuff. When I went to the cryptarc after looking around, he had a green engram for me. I opened it and bam, a hawkmoon. Yes, the only gun iv ever wanted, grinding so long and never getting it, but then I get it from a green engram. Thanks for the memorable moment I was hoping for bungie😑