The Atlantic has a photo essay showing the DIY weapons in used by Syrian rebels. The grenade launcher pictured above is a converted Baikal shotgun. The Baikal is a cheap, but well built, single shot. I own one and I can tell you they are very slow to reload and they have next to no military value. Turning them into grenade launchers is not a bad idea in a time of crisis. On the other hand shooting homemade grenades with an old fashioned lit fuse seems like it might to do more damage to the user than his enemies. I am not sure which is more dangerous, launching a grenade from a shotgun or a giant slingshot. Both concepts make me shudder!