So I am animating a weapon when I ran into this.
The animation:
The animation in-game:
How would I fix this?
From what it seems the mag is not moving where it should instead its going like half the distance.
Also I have the priority set to “Action”
It might be possible your character wasn’t rigged correctly to have the animation run properly. Not sure what tutorial you are using or if you’re trying it out yourself, but I’d recommend going through this tutorial. Hope it helps 
How to animate Tool Parts (Guns, Knifes etc.)
Do you have an animation running continuously? Like a weapon holder animation? If you do you need to stop that animation then run the reload animation.
Yes I have been using this tutorial but still the same outcome