[spoiler]nothing[/spoiler] Edit: deleted b/c of edit 3 Edit 2: The general gist of everyone's responses is to engage it at a range, which makes sense. However unless you're on Widows Court that isn't a very practical strategy. The maps in Destiny just favor close quarters engagements far too highly. Edit 3: After reading most of the responses, I will agree that it isn't [b]unbeatable[/b] but it is too strong. Personally I think the amount of effort it takes for someone to beat a Doctrine in a 1v1 is a lot higher than it is for the person using the Doctrine. Edit 4: Kind of surprised I'm still seeing posts, but just to clarify I meant primaries that consistently work well against the Doctrine. Also try to list ones specifically used in Trials (since that's when those Doctrine users are at their sweatiest). And to get even more specific (if you like) the primary you used to beat a Doctrine on your 8/0 or 9/0 game.