Grenade made during the siege to Madrid for the militias of the Communist party.
It got his name from the unit that used these grenades, the 5th regiment.
It had grooves around the body for fragmentation.
There are two types of this grenade, with the flat lid and with the depressed lid.
This lid was to protect the fuze against humidity.

Length body : 77 mm
Diameter : 50 mm
Weight : 400 gr.
Filling : black powder

Photos and info © Dani.