n 2004, a research report commissioned by the
National Institute of Justice found that should the ban be renewed, its effects on gun violence would likely be small, and perhaps too small for reliable measurement, because rifles in general, including rifles referred to as "assault rifles" or "assault weapons", are rarely used in gun crimes. That study by
Christopher S. Koper, Daniel J. Woods, and Jeffrey A. Roth of the Jerry Lee Center of Criminology,
University of Pennsylvania found no statistically significant evidence that either the assault weapons ban or the ban on magazines holding more than 10 rounds had reduced gun murders. The authors also report that "there has been no discernible reduction in the lethality and injuriousness of gun violence, based on indicators like the percentage of gun crimes resulting in death or the share of gunfire incidents resulting in injury."
https://en.wikipedia.org/wiki/Federal_Assault_Weapons_Ban#cite_note-Koper_204431-31