Do we get the idea they were a bit obsessed with destroying tanks, or in this case probably mostly StuG Assault Guns, since at this point I think the 83rd was mostly still up against the 17th SS Panzergrenadier Division Götz von Berlichingen. The positions seem to be a bit behind the front lines; I assume they were set to catch break-through armor; defense in-depth.
12 July 1944, 330th Infantry Regiment area tank destroyer dispositions
The legend says they were the 3″ Anti-Tank guns, which were pretty good at knocking out what the Germans has in the area. As a previous overlay seemed to indicate: German armor by this stage was not doing well against the 83rd. I assume they were guns much like the one in this photo, reportedly taken in St-Malo.
3 inch anti-tank gun, St. Malo 1944
While the “tank” they most likely were hunting in the bocage looked a lot like this appropriately messed up StuG III. Read more on these work-horse assault guns at https://en.wikipedia.org/wiki/Sturmgeschütz.
StuG III 1945 Germany
Mapping the Overlays 