One is the accuracy, now powerful weapons can fail their targets in long range distance or even close if the enemy is in movement. The mass drivers mostly used by the Black Sun are a very good example.
The other is the blast, that powerful shots fired specially by units from the Black Sun. Now in addition to the accuracy, these weapons can damage more of one hardpoint around the impact zone.
Now you know the two features because at battles as the battle from this video you can watch a Black Sun Megator literally eating star destroyers and bigger things.
Sweet lord, those cannons