This study examined the relationships among trends in deadly gun violence, overall gun availability, and the availability of more lethal types of guns. Using firearms confiscated by the Dallas, Texas, police department from 1980 to 1992 as indicators of the types of guns circulating among criminal/high-risk groups, the project examined changes over time in Dallas' street gun arsenal and assessed the impact these changes had upon gun violence mortality in Dallas. The focus of the project was on the characteristics of the guns rather than their numbers. All confiscated firearms were analyzed and characterized according to basic weapon type and caliber groupings. Dates of confiscation were missing from the majority of the pre-1988 records, but by aggregating the gun data into bimonthly (Part 1) and quarterly (Part 2) time series databases, it was possible to estimate the bimonthly and quarterly periods of confiscation for most of the 1980-1992 records. Records that could not be assigned to bimonthly or quarterly periods were dropped. Confiscated firearms were grouped into basic categories based on stopping power (i.e., wounding potential), rate of fire, and ammunition capacity. The following measures were created for each bimonthly and quarterly period: (1) weapons with high stopping power (large guns), (2) semiautomatic weaponry (semis), (3) weapons combining high stopping power and a semiautomatic firing mechanism (large semis), (4) handguns with high stopping power (large handguns), (5) semiautomatic handguns (semi handguns), and (6) handguns combining high stopping power and semiautomatic firing (large semi handguns). Several violence measures were obtained from the Federal Bureau of Investigation's (FBI) Uniform Crime Reports Supplemental Homicide Reports and Return A (or Offenses Known and Clearances by Arrest) data files (see UNIFORM CRIME REPORTING PROGRAM DATA [UNITED STATES]: 1975-1997 [ICPSR 9028]). These measures were also aggregated at bimonthly and quarterly levels. Data from the Dallas Police Department master gun property file include total handguns, total semiautomatic handguns, total large-caliber handguns, total large-caliber semiautomatic handguns, total shotguns, total semiautomatic shotguns, total rifles, total semiautomatic rifles, and total counts and total semiautomatic counts for various calibers of handguns, shotguns, and rifles. Data that were aggregated using the FBI data include total homicides, gun homicides, total robberies, gun robberies, and gun aggravated assaults. The data file also includes the year and the bimonthly or quarterly period counter.