On my Instagram page, I had a thread about terminal ballistics compared from a 3 inch 38 Special revolver and a 3 inch 9mm revolver. I just so happened to have two basically identical 3 inch revolvers in those calibers, so off to the range I went. Here's the whole video, which is only 9.5 minutes long because I don't like to waste time:
Note: the bullet I identified as the Gold Dot initially in the gel was actually the V-Crown from a different angle that I didn't realize. When I pulled the bullets out I figured out where I went wrong. The 135gr +P 38 Special Gold Dot penetrated about 14 inches and expanded fully.
I was actually surprised at how well the 9mm rounds did until I remembered that a 3 inch revolver barrel has the same, if not more, rifled barrel length as a 4 inch semi-auto pistol.