A total of 75 percent of the men in the sample had owned one or more firearms at some time in their lives. Fifty-seven percent owned a gun at the time of their last arrest. Although the typical gun-owning felon in the sample claimed not to have acquired his weapons for the primary purpose of committing crimes with them, he did so, even to the point of threatening or committing felonious assaults. Given the evident lifestyles of the men in this sample and the likely etiology of the assaults involved, the distinction between aggression and self-protection is unclear. One-tenth of the gun owners reported they had never fired their weapons, and another one-third said they had fired their weapons only once or a few times a year. A total of 57 percent fired their guns once a month or more, and almost one-fifth fired them several times a week. Much if not most of the gun firing was sporting or recreational. In examining the criminal use of their weapons, this study focuses on weapons use in the conviction offense and other offenses and the correlates of habitual weapons carrying. 10 tables.