Quite welcome. Im not sure when certain types of rounds were developed but H.E. had been around for many years. I am not certain when the W.P. rounds came to being. I guess you could say that in a sense, H.E. rounds were grapeshor or cannister even though they were not filled with tiny balls but the schrapnel came from the shell casing when exploding or as on Pinapple handgrenades and made as such a way that more debris is created when the shell or grende casing explodes.

The US Army used these rounds and I suppose they still do. I will try to ask a friend of mine who is a Captain in the army for more on this as soon as I can. This friend was a Company Commander in an Artillery unit but is now with an Armored unit. I will let you know when I find out. Believe it or not, they even had an artillery piece that fired Nuclear artillery shells.

The Germans had a "pinapple" type grenade also. A type for the stickgrenade even had a separate "pinapple" sleeve that could be slipped over the existing stickgrenades sleeve to produce more schrapnel.