I mean if this game is going for realistic vehicles, this should definitely be removed ASAP. This is just a popular myth that is so widespread that these rotating cannons need time to spin up. Its embarassing how long this is in game.
You can ask anyone who flew any F series jet with it if this is the case and you will always get the same answer - it fires when you pull the trigger. Simple.
Is it a myth though cause from all the footage we see, it takes a split second for the gun to wind up. Then it fires. So I would beg a differ. On whether it is a myth or not. However, in-game it is exaggerated.
As you can see above in my video same 20mm Vulcan has been used on every single aircraft since its introduction.
The wind-up is only for a very minor split second. So in-game, it is exaggerated but not by much and honestly isn’t really something that needs to be changed right now.
one the one hand you ask for sources (valid) but write, that it could be also a balance thing.
Why have/ask/want sources at all then for counterparts of weaponry, if balancing it through performance (not br/mm or something) nerfs/buffs is a reason to ignore sources, even if available?
This is highly inconsistend and borderline hypocritical.