Again, my test medium was a smoked pork shoulder. The ammunition used was Remington HD .38 Special 125 gr. +P JHP.
This time I did not hit bone, but I think it would have been just as devasting as the 9mm with maybe a little less penetration. The .38 bullet completely penetrated and left a whole I easily fit my thumb in.
Left is the 9mm, and right the .38
As you can see both rounds expanded as designed and penetrated deeply enough to puncture internal organs. Either, in my opinion, are effective for self defense purposes IF the shooter does his job. Most 9mm pistols are going to hold more rounds than a .38, but considering most defensive use of pistols where shots are fired go less than five rounds this advantage would be marginalized in most situations.
Next up will be the classic .45 ACP.