Help with using layered blend per bone on rifle animations?

i am trying to make my character Equip,Unequip and use rifle animations on the upper body while it has a locomotion statemachine on the lower body. The problem happens when my character unequipped the weapon then the animation in the upper body is playing as the default A-Pose of the UE mannequin while working perfect on the lower body, I use Layered Blend Per Bone blueprint and If i use a bool variable to disable/enable the weights then it wont play the Unequip animation properly. Does anyone know what to do so i can make my character use upper body rifle animations?