I'm always a bit suprised over the facination over the use of the German '88' vas tanks and ground targets. Folks act like it was something special, unique, or whatever. The whole concept of a multipurpose medium artillery weapon had been around for a couple decades
One early proposal for such a weapon was from the former Austrian artillery officer General Ludwig Eimannsberger. In the early 1920s Eimannsberger proposed a 'Tank und Flieger' "TuF" artillery weapon for the Austrian army. Specifically a 75mm gun mounted on a cruciform platform/carriage, equipped with fire control equipment for indirect fire, AT fire, and anti aircraft fires. Eimannsberger provided detailed specifications for weight, range, projectiles, elevation, ect.. Gudmundsson has a couple pages on Eimannsbergers proposals in 'On Artillery' (pages 116 - 118)
This was certainly not the only emergence of the concept. In the early 1920s the 'Westerveldt Board' recommended pursuit of a multipurpose artillery weapon for the US Army. One of the reusults of this was a 75mm cannon on a T3 mount. This was intended for use as a field artillery, antiaircraft, and antitank weapon.
Found several pages of text on this weapon in the 1930 issue of the US Field Artillery Journal. Vol XX May-June 1930 #3. The specific article concerns the future division artillery and describes the several cannon of gun and howitzer types being designed for the US Army. Starts on page 239 if my notes are correct.http://sill-www.army.mil/firesbullet...ves/index.html
There are eight photographs of the cannon/carriage and two scale drawings. The text identifies it as 75mm cannon on mount T3. The dozen odd pages of text concerning it discuss its multipurpose role as a indirect fire, anti tank, and antiaircraft artillery weapon. Fire control equipment designed and tested for this weapon included 'long tube' style range finders, a mechanical or analog moving target computational machine, a electrical transmission system of firing data (range/elevation, direction, fuze settings) from the battery computations section to the individual guns. One photo shows the repeater device for range/elevation on the cannon.
Development seems to have been initiated in the early 1920s and testing occuring circa 1928-1930. Within the US Army development was ended with the fiscal constriants of of the US government of the 1920s and the subsequent Depression years. While 75mm & 3" guns went into production as tank & AT weapons from 1940 the T3 carriage and universal cannon concept disappeared from the US Army, other than training of the antiaircraft artillery for use against ground targets.
I did not have time to do more than skim the article, so if there was anything about ammunition I missed it.
For miscl sources similar weapons seem to have been proposed within the British, French, German, & possiblly Dutch armies. I'd not be suprised if the same general idea was not considered by others, or even tested.