Is the original source of that photo even known, and if so is it actually trustworthy? Anyone can put together a good-looking photo.
Even if it came right from the FBI test labs, basing your opinion on one photo is not very smart.
Yes, ballistic gel can show you something. But it has been said time and again by expert sources that it is not directly comparable to human tissue. When many of those same expert sources also relate real-world info from the field indicating there is negligible difference between calibers, not taking this into account is willful ignorance.