There have being cases were expanding ammo has not penetrated enough the Miami shootout for example.
Poor example. The 115 gr. Winchester Silvertip traveled through Platt's right upper arm and through most of the lung, stopping about inch short of the heart. The round caused Platt's lung to collapse and was likely the fatal round. http://www.firearmstactical.com/briefs7.htm
. It just didn't kill Platt fast enough. He was a well-trained, highly motivated bad guy. The shootout showed that handguns are inadequate in those types of situations unless you hit the central nervous system. Sure, another inch would have been better in this specific situation but you can't bank too heavily on one bullet in one incident.