On long range sniper ships Locknigar is a good way to increase your dps. The gunner has to develop a rythem:
Shoot Charged round, Shoot Charged round, Load Locknigar, Line up shot, Shoot Locknigar, Hit gun with mallet, Load Charged round, Repeat.
Assuming the captain is not flying erratically you can put out significantly more hurt with Locknigar and charged rounds than you can with charged rounds alone. Also when the dammage is delivered in one big dose the engineer has less time to fix it.