This involves an augmentation to something we already have. Think of an Auto Turret with a chair on top of it. When a Knight climbs into it, they can rotate the gun and fire it. Bullets would be similar to an Autogun but more accurate, and deal a moderate amount of damage to monsters.

Attacks directed toward an occupied Rotary Turret would only damage the Turret rather than the Knight, but the Turret itself would have relatively low HP. It would also despawn after a certain amount of shots fired, and would be stationary throughout.