Made this quick little snowball grenade maker after the kids I were having lots of fun with the dodecahedron snowball maker. Wasn't able to find a grenade mold that fit my likings so I thought I'd whip one together. 

I printed this model standing upside down on its top. Supports are not really required at all however I did use a couple tiny ones on the outside of the right mold piece, these likely weren't needed at all. Haven't given a go yet without but I'd imagine you would give better opportunity for a brim without the supports on that half. 

Printed in PLA+, 10% infill, 0.2mm layer height.