I have noticed the following issues with the sniper rifle both in the example APK and when launching the game myself:
1/ the arming handle is on the same side as the hand holding the rifle. For example if holding the rifle with the right hand, the arming handle is on the right side of the rifle, making it difficult to do with the left hand. But maybe it was a deliberate design choice.
2/ when changing hand, the rifle gets inversed. But in the process, the scope is not working anymore (the SceneCapture2D is not displayed). When switching back to the other hand, the scope works normally again.