Your SCAR has some mesh issues, you have a lot of unnecessary edges that you don't need, remember that if the surface is flat without any detail, you don't really need to add any edges to it, and that you can put details as separate meshes not directly connected to the mesh itself.
Quote: "And I don't know how to make realistic looking textures."
I generally just do it by hand, it tends to be pretty fun and makes you understand a lot about lightning and such, as with everything practice makes perfect.

Alucard94, the member of the future of the past.