Let’s begin our look at some of the studies
“First Study Indicates a Decline in Criminal Use of Assault Weapons,” March 28, 1997
“Title XI of the Violent Crime Control and Law Enforcement Act of 1994… required a study of the effects of these bans, with particular emphasis on violent and drug trafficking crime, to be conducted within 30 months following the effective date of the bans. To satisfy the study requirement, the National Institute of Justice (NIJ) awarded a grant to The Urban Institute for an impact evaluation of Subtitle A. This report contains the study findings.”
“At best, the assault weapons ban can have only a limited effect on total gun murders, because the banned weapons and magazines were never involved in more than a modest fraction of all gun murders. Our best estimate is that the ban contributed to a 6.7 percent decrease in total gun murders between 1994 and 1995, beyond what would have been expected in view of ongoing crime, demographic, and economic trends. However, with only one year of post-ban data, we cannot rule out the possibility that this decrease reflects chance year-to-year variation rather than a true effect of the ban. Nor can we rule out effects of other features of the 1994 Crime Act or a host of state and local initiatives that took place simultaneously. Further, any short-run preventive effect observable at this time may ebb in the near future as the stock of grandfathered assault weapons and legal substitute guns leaks to secondary markets, then increase as the stock of large-capacity magazines gradually dwindles.
We were unable to detect any reduction to date in two types of gun murders that are thought to be closely associated with assault weapons, those with multiple victims in a single incident and those producing multiple bullet wounds per victim. We did find a reduction in killings of police officers since mid-1995. However, the available data are partial and preliminary, and the trends may have been influenced by law enforcement agency policies regarding bulletproof vests.”
Requests for Bureau of Alcohol, Tobacco, and Firearms (BATF) traces of assault weapons recovered in crime by law enforcement agencies throughout the country declined 20 percent in 1995, the first calendar year after the ban took effect. Some of this decrease may reflect an overall decrease in gun crimes; total trace requests dropped 11 percent in 1995 and gun murders dropped 12 percent. Nevertheless, these trends suggest an 8–9 percent additional decrease due to substitution of other guns for the banned assault weapons in 1995-gun crimes.
The report concluded that the legislatively mandated review period was both too short and too close to the beginning of the assault weapons ban to adequately judge the ban's effect on street violence
https://www.urban.org/research/publication/impact-evaluation-public-safety-and-recreational-firearms-use-protection-act-1994 by Jeffrey A. Roth, Christopher S. Koper, William Adams, John E. Marcotte, Doug Wissoker, March 13, 1997, The Urban Institute
“It is therefore difficult to make any definitive statements about the use of large-capacity magazines in crime since the ban.”
“Our ability to discern ban effects on these consequences is constrained by a number of facts. The potential size of ban effects is limited because the banned weapons and magazines were used in only a minority of gun crimes — based on limited evidence, we estimate that 25% of gun homicides are committed with guns equipped with large-capacity magazines, of which assault weapons are a subset. Further, the power to discern small effects statistically is limited because post-ban data are available for only one full calendar year. Also, a large stock still exists of grandfathered magazines as well as grandfathered and legal-substitute guns with assault weapon characteristics.”
“Our best estimate of the impact of the ban on state level gun homicide rates is that it caused a reduction of 6.7% in gun murders in 1995 relative to a projection of recent trends. However, the evidence is not strong enough for us to conclude that there was any meaningful effect (i.e., that the effect was different from zero).”
“Second, we recommend further research on the role of assault weapons and large-capacity magazines in murders of police officers. Our analysis of police murders has shown that the fraction of police murders involving assault weapons is higher than that for civilian murders. This suggests that gun murders of police should be more sensitive to the ban than gun murders in general. Yet, further research, considering such factors as numbers of shots fired, wounds inflicted, and offender characteristics, is necessary for a greater understanding of the role of the banned weaponry in these murders.”
https://www.ojp.gov/pdffiles1/173405.pdf, March 1999, U.S. Department of Justice, Office of Justice Programs, National Institute of Justice, “Impacts of the 1994 Assault Weapons Ban: 1994–96” https://nij.ojp.gov/library/publications/impact-1994-assault-weapons-ban-1994-96-research-brief, by Jeffrey A. Roth and Christopher S. Koper
· The ban’s impact on lethal gun violence is unclear….
· Although the weapons banned by this legislation were used only rarely in gun crimes before the ban, supporters felt that these weapons posed a threat to public safety because they are capable of firing many shots rapidly
· The ban’s impact on lethal gun violence is unclear because the short period since the enabling legislation’s passage created methodological difficulties for research
· A number of factors—including the fact that the banned weapons and magazines were rarely used to commit murders in this country, the limited availability of data on the weapons…posed challenges in discerning the effects of the ban.
· Criminal use of the banned guns declined, at least temporarily, after the law went into effect, which suggests that the legal stock of pre-ban assault weapons was, at least for the short term, largely in the hands of collectors and dealers
· Evidence suggests that the ban may have contributed to a reduction in the gun murder rate and murders of police officers by criminals armed with assault weapons [or perhaps weapons that only resembled the banned weapons]
· The ban has failed to reduce the average number of victims per gun murder incident or multiple gunshot wound victims.
· The banned guns are used in only a small fraction of gun crimes; even before the ban, most of them rarely turned up in law enforcement agencies'
· Findings indicated that the public safety benefits of the 1994 ban have not yet been demonstrated and suggested that existing regulations should be complemented by further tests of enforcement tactics that focus on the tiny numbers of gun dealers and owners linked to gun violence