https://gunsoficarus.com/community/forum/index.php/topic,3059.0.html (arming time guide)
The Light Flak has an effective range of 225m-875m, which is a pretty narrow band. I'd like to see the range increased to a little over 1000 or so. I think the damage is in a good place, as it's a pretty accurate weapon over a longer range. It's easier to aim and connect hits with than the heavy flak, and it does more damage than the artemis. If it was able to destroy ships in a single clip it would probably push the game to more sniping matches.
It has 6 shots, dealing about 75 explosive damage in it's effective range. That's about 630 hull health damage (1.4 modifier). So it can take out a junker, but that's about it. (Junker has the lowest value of hull health). Buff it and make good ammo choices and it's another story.
Buff alone brings it up to 756 hull health damage over the clip, which is enough to 1 clip most ships. Burst alone takes it to 735 (although it takes longer to empty the clip), and burst+buff 882 damage. Heatsink+buff will take it up to 836-ish. Charged+buff goes to 819.
Normal takes 2.4 seconds to empty the clip, where burst takes 3.3 seconds. Heatsink will take 3.2, and charged will take 2.67 seconds.
All in all it's pretty effective in the damage/time-to-kill department. It can't compete with the mortar of course, but the range generally makes up for that. (mortar is 0-400 meters and travels much slower).
As for the artemis, a full clip only does about 440 total hull damage per clip and takes over 6 seconds to empty the clip. Regardless of buffing and ammo type, the flak comes out on top for damage.