I tested all the cannon class guns on turrets, I don't think flank guns work right now. Sniper guns suck do to the turret AI needs work. Rapid cannons work but seem to tear large sections of blocks out. In one test a Isanth-VI had about 40% of its blocks before they hit the core. Shotgun has a similar end but is faster IF you are point blank otherwise its slower if your at range. Artillery has a low aim % but hits hard, pops blocks fast. But i tested lock on missiles as was suggested. Lock on missiles are easy, they do not shoot every thing any more. and 3 to 4 missiles kill a Isanth 6 in a min.