If you need a visual reference, then Google Image Search has you covered. Just, remember to turn off safe search, and bring a strong stomach. Understandably, this isn’t pleasant viewing material.
I think this is the most detail I’ve gone into on specifics for gunshot wound forensics, even if the specific discussion had to do with 18th century pistols. Though we do have a gunshot wound tag, and there’s a mix of stuff in there that might be useful.
Also, I think I’ve identified it before, but I tend to use the Howdunit Forensics book preferentially as a resource, so if you need a closer look on how and why gunshot wounds behave the way they do, that’s probably worth looking at.