They were all well clear of the plasma cannon.

At the near end, a big drive cone and/or plasma cannon drifted past.

A clear disadvantage of the plasma cannon is its weight.

But there were several plasma cannons to make up the lack.

If they'd hit us with a plasma cannon first, they would have- Wham!

Something happened in that arm, and the plasma cannon ceased to track.

The remaining plasma cannon on the wall level opened up simultaneously.

He turned to his team and gestured at the folded up plasma cannon.

He was poised over the key that would trigger the four plasma cannon.

The main difference was his plasma cannon, sighted down the corridor.