I made these bullets in 3D Studio Max, and rendered them out in separate passes. I personally loved the Reflection pass, it came in so handy with it's almost-unnoticeable HDRI.
Color correction has always played an important role in compositing and in this case the bullets had to undergo a few corrections. Originally they were given a golden/brass diffuse but I preferred a more red-like color. I added a small camera move inside of After Effects to show-off depth. And a camera-lens blur to top it all off - I find that there is some problem with it though, in that there is something wrong with the focus, maybe the order in which the lens focuses is a bit off but feel free to correct me.