With HTML5 , firebird is not powerful at all , even when it is equipped with supplies like double damage , double armor or etc ....
Firebird is just as powerful in the HTML5 version as it is in all other versions of the game. What I think you are running into that could decrease the power of your turret is other Players having protection modules against your turret, which would decrease the overall damage they take from your turret, or they could be using Heat Resistance or Heat Immunity, both of which have the same effects of lowering the amount of damage an opposing Firebird deals. You can find information about protection modules here, and information about Hull Augments in this article.
Hope this helps!
I agree with the questioner. I observe two things as I play an hour plus everyday
for several years now. First, new Overdrives and other modifications
seem to have made ranged weapons stronger, as compared to proximity weapons
like Firebird, Isida and Freeze. Second, many hulls and
augmentations now seem to shrug off my flame
attacks. Admittedly I am biased, because I am a dedicated
Firebird user, but I remember fondly when flames struck fear across the
battlefield. Now, even though I am Mk7-11, enemies seem to shrug off
Customer support service by UserEcho