During one of my postings I became with acquainted with a Dr. who had relocated here from South Africa. He was extremely over qualified for small town work, but he brought with him a wealth of experience. He told me accounts of working in the ER in a large city in SA whereby he treated numerous gunshot wounds almost every evening. He said he could recognize a 9mm ball round wound as he merely did some quick treatment and often sent the person on their way - as long as the hit was not in vital areas, etc. More often than not, it was police officers that he sewed up from these ball round hits as that is what most of the criminals had at their disposal there. He said any caliber with a hollowpoint round was an entirely different story. Much more serious wound trauma and the outcome was not always so certain.
That being said, I asked him about the age old .45 vs 9mm debate. He said that 9mm ball was poor, but the .45 fmj round was considerably more effective in its effects on humans - but he rarely saw it used as .45 pistols are not all the rage there.
Just food for thought. I carry hp's.