I didn't save it when I added the support edges, that is why they aren't in this SS, but this is the normal map that it generated with the support edges.
Hi! Maybe I didn't word it right: Yes, border edges are looking straight, but the vertices on the edge are not distributed evenly. Split the corners like so to avoid UVs stretching:
Your models are clean, but the lighting doesn’t give them much justice. It also feel like they’d benefit, as iam said, of textures that are a bit more worn-out, some dents and irregularities. The knife in particular doesn’t feel like a knife because it’s too clean. I’m not too much for the dents on the gun as it’s a game…