Two guys named Thompson and LaGuardia shot all kinds of tissued things with flatnose and roundnose bullets and the .455 manstopper bullet which looked like a big, fat .45 caliber hollowbase wadcutter that was reverse loaded.
Their conclusion was the flatnose bullets outperformed everything else in living tissue, especially if the caliber was of .4 or larger.
All this happy testing took place near on eighty years ago and not much has changed since then.
By the way, the top of the bullet, be it round or flat is called the metplat.
Ever wonder why the light charge hollowbase wadcutter .38 Special load was developed?
It would fit in old .38 Long Colt revolver chambers and the hollowbase would upset the bullet enough to fill the generous bore dimensions of those old Colt double action revolvers and allow them to shoot with a modicum of accuracy.
It was also extremely accurate and powerful in the .38 long Colt chambered S&W Military and Police revolver.
A 90 year old gun crank told me that bit of history and it makes more sense than any other reason that has been put forth.
He claimed that the hollowbase load was the first real .38 'Special' load, the 'Special' load was intended to improve the performance of the original .38 Long Colt load, which it did, and an engineer at Smith and Wesson got the bright idea to load 158 grain bullets in the longer special case, pump the powder charge and velocity up to get 900 feet per second instead of 765 feet per second and lengthen the chamber of the S&W Military/Police revolver to accomodate them.
Some refinements had to be made to the gun because the pressure was higher than the engineer expected but all worked out and now you know,,,,the rest of the story.