I almost never buy them, I only get them from loot chests, the Gunsmith and Eris, I have never bought them from Xur. I can agree that they are obviously very useful but I hardly use them, I just get through the level with my skill and trusty Primary and Special Weapons and when Heavy Ammo drops, all is well. I really don't see what the big deal is. Edit 1: I have done both raids and I do agree that Synthesis' are useful but enemies still drop heavy ammo. Edit 2: Wow so many butthurt responses about how I have "never done a raid" and all that shit, only a couple good responses so far... Edit 3: Geez, I didn't think I would have to edit this 3 times but I guess I do to say this: Who freaking cares how many times I've raided? Maybe I don't like the raids, maybe I can't ever find a good fireteam, maybe I just don't have the time. Just please stop giving me crap about this. Edit 4: So I guess I chose the wrong words for my title so I'm going to restate it: "Why are people bitching so much about Xur not selling Heavy Ammo Synthesis?"