So there seems to be a new forend coming from Mesa Tactical to fill in the gap from when Surefire stopped making theirs. Looks nice and adds the attachment points you need unlike the stock forend.
https://mesatactical.com/products/truckee-forend-for-the-benelli-m4.html
https://mesatactical.com/products/truckee-forend-for-the-benelli-m4.html


















































