Summary

The 75x640mmR was used in Germany's Panzerkampfwagen V Panther tank during WW2
This massive piece of artillery measures 35.25 inches tall and takes about 700 grams of filament

Here is a link to another model of this round on cults3d: https://cults3d.com/en/3d-model/various/ww2-german-7-5cm-kwk-42-panther-tank-cannon-shell
Here is a link to similar models on thingiverse: https://www.thingiverse.com/thing:6964076