Raycasting from object rotation?

Does this ray change rotation as you change the rotation of the "Gun"?

We need to understand your setup and see your code. Typically you would cast from an empty game object positioned at the tip of the gun and a child of the gun. The forward (positive z) side of that empty game object would align with the barrel of the gun. Then you would use 'transform.forward' as your direction for your ray.

The ray does not change rotation as I change the rotation of the gun. I want a ray to cast with the rotation of the gun, not set to a specific axis.

'transform.forward' is the forward direction of an object in world space. It changes as the object is rotated. You can use the transform.position and transform.forward in the Raycast().