Yes, David, it was a bullet removed from a person. I have seen many in person, and far more in photographs.
If you use the links I posted, you should be able to find some good information. One you should look for, is Eugene Wolberg's study comparing recovered bullets from officer involved shootings, with the same rounds fired into 10% gelatin. The bullets performance were statistically identical. It was one of the studies used to prove the accuracy of gelatin testing. If the bullet expands in properly calibrated gelatin, it will expand in tissue. If your people are using telephone books, you may wish to make some changes....
Again, today's better ammunition, not expanding, unless it was plugged from a barrier, would be very strange, and should be cause for concern. I have occasionally, seen a lot of ammunition that was considerably underloaded, which can impair performance, including expansion. Good reason to regularly chronograph ammunition used for duty.
This is why it's so important for bullet performance to be evaluated by trained personnel. Anecdotal information is useless. We've all heard the stories like "the bad guy was shot 19 times with 9mm with no effect." Then when you read the report, the crook was shot at 19 times, and was hit twice, once in the foot, and once in the thumb. Some Gunwriters are famous for throwing these kinds of stories into their articles, usually to help prove, (or promote....), the effectiveness of a particular round or caliber. Look to scientists for your data.... not writers......