Back (Rod Grenades, WWI)

Austro-Hungarian Zeitzünder Gewehrgranate, 1st & 2nd Variants
and Parts Comparison with the Rohrhandgranate

These are Austro-Hungarian Zeitzünder ("time fuze") rod grenades, used during WWI. The serrated fragmentation type is the first variant, the smooth bodied grenade is the second variant, the Model 16.
Both have the same inertial pull-fuze. When fired, the weight of the end piece would pull the friction igniter, automatically setting the time delay. Also, by just removing the rod, they could be used as hand grenades... one of the useful features of this type of time delay fuze. (Total length 880mm) 

The first variant is heavily segmented, both inside and out, one of the most dramatic grenades in this regard. The second model is very simple, just a plain cylindrical casting. Apparently, extra range was the goal for that version. Considering that the typical WWI battlefield was very soft & muddy, this grenade probably wasn't very effective, as if it hit the ground before detonating it no doubt buried itself quite well.
A comparison of the Zeitzünder rod grenade can be made with its hand grenade counterpart the Rohrhandgranate. The body style is identical, threaded at both ends, allowing different fore and aft pieces to be substituted so the center casting could be configured to be either a rifle or hand grenade. I'm guessing this would usually be done at the factory.This hand grenade example is staked across the plug of the wire handle. But this also could have been a configuration made in the field, depending on need. (A useful feature)
All things considered, this seems to be a pretty versatile design that was easy to manufacture. One significant drawback however is its extreme weight and cumbersome size.. Any additional info / corrections ?

One side note....
Apparently the nick-name "Guguruz" was applied to this grenade. There is no translation for this Austrian word. A Guguruz is a type of corn, the shape it somewhat resembles, so they named it that. Much like the American word “pineapple” applied to fragmentation grenades.
Curious that hand munitions have had food related nick-names applied to them by solders around the world,
(i.e. pineapple, lemon, potato masher, pear, egg ... to name a few)