Question: destiny 2 how to unlock golden gun?
Answer: Run Public Events, Lost Sectors and kill some HVTs then loot the chests. Inside there's a chance for you to pick up a relic called the Melted Hand Cannon; once you have it you just need to kill and participate in stuff to fill the bar to 100% then do a mission to unlock it. It'll be the same way for the Nightstalker.