Cannot line up sights when crouching (FPS Game)

Hi All!

I am currently working on creating a FPS game in Unity and I am having trouble lining up the crosshairs of the gun with the middle of the screen while my player is crouching. I use animations to move the gun from its position by the player's side to the center of the screen and this works while the player is standing. This is working well since the gun stays in a fixed place no matter where I look on the map.

However while my character crouches, the gun does not stay fixed, which is why it won't line up with my animation when I'm trying to aim while crouching. I was wondering why the gun no longer stays in one place when I crouch and look around the map and any steps I can make to fix this issue.