HELLO,CAN ANYBODY SHEID SOME LIGHT ON MY F1 I HAVE A WW1 FRENCH F1 GRENADE WITH THE 1916 FUSE EVERYTHING LOOKS GREAT,LIKE THE OTHER 3 I HAVE BUT THIS ONE HAS A LEAD SCREW IN THE BOTTOM JUST LIKE THE EARLY MK2 U.S. GRENADES.IS THIS A RARE DESIGN OR IS IT COMMON,AND WHAT IS IT FOR.THANKS AHEAD OF TIME.:tinysmile_twink_t: