Cross Bow, M4,M14, Katana, M67X

[-{ET}-xdEpicZombie]

Your models should definitely not exceed 10k verts or polys.try to get it done with 2k-4k polys.
I do use background images,drag and drop to add,make sure you are in ortho view.UV Mapping isnt my strongest side but yeah you can uv map in blender.If you are using the latest blender version there's a tab on the left side of the screen "Shading/UVs".You'll find a thing called "mark seams".Seams are some edges that you choose and then mark(they turn red) which will be cut in order the program can render 2D image-a UV map.Fairly simple thing but is a pain in the ass if you are dealing with more complex models.