The deck guns are “backfiring” and not shooting the dreadwings. There is a very narrow area on the right where they can be shot and I’ve managed to reach 27/30 but the dreadwings stop flying into that narrow area. The bug persists after taking these actions:
Disable add-ons, reloadui, exit game
Abandon quest, reaccept quest
Hearth off the ship, return to Dalaran, reenter portal in Violet Citadel
I’m unable to start the Stormheim quest storyline.
Having the same issue. Thanks for reporting.
This happened to me earlier today as well. Cannot complete quest. My wife could because she’s a Hunter and has range. I do not.
having the same issue, canons are firing on themselves no matter the angle i try. i can’t finish the quest.
Glad I’m not the only one! There are a few other posts about this too. Seems to be a problem with cannon mechanics after the patch.
Having the same issue.
Abandoned it the first time.
Spent probably an hour messing around with different guns and strategies.
Got to 27 of 30. Impossible to get 3 more to complete it.
I sent in a problem ticket. No response yet. Going to bed 
Omg I’m so sad I spent hours becoming friendly with different areas of the broken isles just to end up not being able to get through the stormheim quests because of that stupid bug! I thought it was just me. I really wanna unlock the allied races but this quest if stopping me from doing that!
Same I spent hours
Same, I just started this today and have been trying for over an hour.
This is exactly the boat I’m in right now. The Stormheim is the last rep I need.
Ya I gave up cause I know it’s not gonna work til the bugs fixed really sucks 
Same here… real problem makes the whole zone start fail… this is a new issue since 9.1.5
Please fix!!!
Hey Guys,
I managed to get past this part even with the bugged deck guns. For some reason, the quest restarted me in Stormwind. so i talked to the captain and Greymanes gambit restarts.
As soon as it starts I get on the right-side gun all the way towards the back. (aft starboard?) then I just find that spot where the gin works and shoot everything… in the very beginning of the quest, there are a ton of the bat riders in that area.
I hope that helps!
Mark me as having trouble with this quest. It’s a shame since Stormhein is my favorite zone in Legion
Partial workaround: If you have a ranged attack, go to highest part of ship and every few moments some of the targets get close enough to engage them. Got a few that way, then went back to guns and noticed some more had returned to the area I could hit with the guns. Was able to complete the quest then. If they wont fly back into the area you can fire on then just stick to engaging them when they fly close to top most part of the airship. Annoying but allowed me to get past it.
I got through it by climbing to the highest point on the ship. Back where the captain stays worked for me and then i could insta-cast and 1-shot the last few dreadwings that i needed to complete the quest. I was probably only able to do it because i am lvl 60 mage and could insta-cast, 1-shot them.
It’s not by design, but this trick may help a few of you get past it.
Having the same issue. Had to death grip a few things towards me to get my last few on my DK. Incredibly annoying.
Same issue here
Same problem. I spent at least 1-2 hours between restarting the quest, swtching the timewalker settings with Chromie, and trying to get above 24/30 (which itself took 20-30 mins for enough fliers to come into the very limited range). Something is very off with the guns in that they think they are “blocked” despite nothing being in front of them, resulting in them exploding their shots right after shooting instead of firing into the sky as intended. There is a very narrow area where they will fire properly but as noted there aren’t enough mobs that fly into that area to meet quest objectives, so there doesn’t seem to be any workaround.
I tried this on several new characters, all with the same issue. I had previously run Legion a few months ago with no problem in this quest, so it is a relatively new issue.
are they willing to fix the bug…