Failures to stop a suspect because of under-penetration, poor bullet placement, and completely missing the target are far more significant problems than over-penetration. With shots to the center of mass, if a handgun or rifle bullet fails to have enough penetration to reach the large blood bearing vessels and organs in the torso, rapid physiological incapacitation is unlikely and an opponent may remain a lethal threat to officers and citizen bystanders. Conversely, if a bullet fired by officers completely penetrates a violent criminal and exits downrange, the bullet will certainly have had enough penetration to reach the large blood bearing vessels or organs in the torso. As a result, it is more likely to have caused sufficient hemorrhage to induce hypovolemic shock--the only reliable method of physiological incapacitation in the absence of CNS trauma.

Unfortunately, according to the available published date, the majority of shots fired in the field by U.S. LE officers miss their intended target. According to published NYPD SOP-9 data, the NYPD hit ratio by officers against perpetrators in 2000 was 12.3% of shots fired and in 2001 13.5% of shots fired. The Miami Metro-Dade County PD had hit ratios ranging between 15.4% and 30% from 1988-1994. Portland PD reported hits with 43% of shots fired at adversaries from 1984-1992, while Baltimore PD reported a 49% average hit ratio from 1989-2002.

Given that the reported averages for LE officers actually hitting the suspect ranges between 12% to 49% of shots fired, more concern should be given to the between 51-88% of shots fired by LE officers which completely MISS the intended target and immediately result in a significant threat to any person down range, rather than excessively worry about the relatively rare instance where one of the 12%-49% of shots fired actually hits the intended target and then exits the perpetrator in a fashion which still poses a hazard.

In short, the consequences of projectile under-penetration are far more likely to get officers and citizens killed than over-penetration issues.