In the military history field Brandt is best known for his revolutionary improvements to mortars and their ammunition.
In the late 1930s, however, he began work on improving large-caliber ammunition. Little has been known about this aspect of his genius, but fortunately he sent brochures, drawings, specifications, tests, and photos of his work to US Army Ordnance. These reveal long-range artillery ammunition, APDS anti-tank ammunition, and AP ammunition with impact flash elements, all well in advance of his contemporaries around the world. These were not mere paper studies, but actual hardware prototypes made by his factory in France, although he and his family had fled to Switzerland in 1939.
Students of the history of large-caliber ammunition will find a lot of cool information here.
25mm visible impact AP round (description)
25mm visible impact AP round (performance)
75-58mm APDS round for M1897 gun
75-66mm APDS round for M1897 gun
75mm sub-caliber for M1897 gun