Handgun bullets expand in the human target only 60-70% of the time at best. I think that when one considers stopping power of a handgun round it is best to assume worst case scenario (your hollow point does not expand 40% of the time). I do not think that all Julian Hatcher's information is out of date. The point of this article is that bullet weights over 179 grain that are .40 caliber or larger will penetrate more tissue and cause damage thereby hopefully defeating your opponent more effectively than smaller caliber speedy rounds. Some of the information may be incorrect but there are things we can learn from Hatcher's work.