Add this float to the Equip interface event, and make sure you set the default value to 1 like shown in the image above and compile. If you do not do this other animations in the system will not work!
Navigate to the location shown at the top of the screenshot and add the Reload Rate variables like shown in the image. You do not need to create these variables they already exist.
Connect the play rate to the play montage node
Add these node shown above