I'm not a ballistics person, but I do work in photoshop a good deal.
Check out the rough pixelization all over the entire photo. The "bullet fragments" do not have any of this pixelization anywhere.
I have created "fragments" that look exactly like that using the "zoom blur" filter in photoshop.
I'm not saying it's a fake (I can't really see any reason to fake that pic), but it looks like something I could have created on the computer. :)
Here's a link to my personal site. The background resembles the "bullet fragments":
Also, all of that "equal and opposite reaction" stuff I learned in high school doesn't seem to make sense here. The fragments have already traveled several inches, but the spinner hasn't budged. Oh well.