Question Finding Position on a Canvas

We use a mounted gun with a stagnate third-person camera for my ship warfare game. However, now tasked with implementing an aiming reticle I am having trouble getting the position right on my Canvas. I've been trying to implement a ray cast from the gun to a camera-space canvas and using the hit position for the reticle.

Does anyone have any suggestions?

I am currently rotating the gun through a simple message-based system and clamping before applying, code below

Code (CSharp):

1.     private void OnLook(InputValue value)
2.     {
3.         _rotateValue = value.Get<Vector2>();
4.         ApplyRotation();
5.     }
6.  
7.     private void ApplyRotation()
8.     {
9.         var xLook= _lookRotation.x - (_rotateValue.y * mouseSensitivity * Time.deltaTime);
10.         var yLook = _lookRotation.y + (_rotateValue.x * mouseSensitivity * Time.deltaTime);
11.      
12.         _lookRotation.x = Mathf.Clamp(xLook,-xClamp, 0);
13.         _lookRotation.y = Mathf.Clamp(yLook, -yClamp, yClamp);
14.  
15.         rotateObject.rotation = Quaternion.Euler(_lookRotation);
16.         onObjectRotation?.Invoke(_lookRotation);
17.     }

I am afraid I'll have to change it up to focus on the reticle and having to rotate the gun towards it, but wanting to prevent extra work ^^'