Few thing I've learned by doing them wrong in this model: you should triangulate your mesh before exporting, to avoid errors on the texture later; I considered taboo to have overlapping UVs, because of light baking and texturing, but it turns out it's better to have mirrored parts with overlapping UVs, gets you a lot more resolution, if you know for sure those 2 sides will look the same, although there are a few tricks using extra parts to hide the mirroring.
50x50x50 cm 2414 Triangles Modeled in Blender Textured in Substance Painter
While a metallic texture was created, it was unnecessary, seing that the model is fully metallic everywhere.
The concept for this model was given by Big Moxi Games as part of a 3D Artist test.
Green Loot Box