Modelling the Projectile
Draw another line and change the smoothing options to bezier-corner where needed. (Fig.08)
Add Lathe and smooth modifiers and align the projectile lathing with the shell (you can copy and paste the lathe modifier from the shell).(Fig.09)
The bullet modeling is now finished. (Fig.10)
Add a UVW Mapping modifier. Change the projection to Cylinder, enable "Cap" and change the Alignment to fit the length of the shell. (Fig.11)
To check our mapping so far, add a Checker map (with high tiling settings (let's say 20 each)) and add it to the model. We can see that in the Casing part of the model, the squares are more rectangular and the Rim squares are much smaller: (Fig.12)
Play with the mapping settings (length, width and height) in order to have 'all square - equal sized' squares.
Now this next part is bit tricky (and not so detailed)...
Add a UVW Unwrap modifier. Click the Edit button. You can see that the Casing and the Rim mappings are overlapping. Choose the Face sub-selection, uncheck Ignore Backfacing and select all the Rim polygons. In the Edit window, move them to an unoccupied place. Select all polygons and scale it down so all polygons fit the blue box margins. Still in the Edit window, choose Tools > Render UVW template. I chose 2048 x 2048 resolution (try staying in 2n power values) and hit Render UV template. Save the render; we will use it later to texture.(Fig.13)
Use the same technique for the projectile. This time, I rendered the UVs on 1024 x 1024.
Open the texported Shell UVs in Photoshop. Double-click the locked layer (Background) to unlock it. Press Ctrl + I to invert the colours. Double-click again on the layer and move the right blending spinner to delete the white colour from it. From this moment on, this will always be the utmost layer.(Fig.14)
We will now use some metal textures I found in a simple Google search, here. (Fig.15, 16. 17)