Hey everyone,
For those considering light mounts for their Benelli M4, Mounting Solutions Plus just released a great option. They have a Scout Light Mount specifically designed for the Benelli M4, which is compatible with the Surefire M600DF and other original Scout body lights. You can find more details and purchase it https://www.mountsplus.com/msp-scout-light-mount-for-benelli-m4.html
This mount keeps the light snug to the gun, which is great for minimal interference.
Hope this helps!
Full disclosure, I do work for Mounting Solutions Plus .