Hello nice bunch of grenades.I think that the fuse is the late war "flat" version and dates to around 1917. I have a picture of one in a book with this same fuse. The early grenades had a cone shaped fuse that was produced around 1915. Most that you find don't have the fuse. My opinion is that the fuses were salvaged for the brass and the bodies discarded.
Thank youHi vinnyw,
I doubt these were very reliable. They are also quite heavy and it would take a lot of strength to throw these very far. I dont know a whole lot about them. Ive seen a photo of one of these on a catapult launching device. Maybe that is what the ring is for? These are the ones I have come across in my 10+ years of collecting.
Thanks!