Although tens of thousands of Americans die from gun violence every year, the regulation of firearms remains inadequate. Those who are injured, or the survivors of those killed by guns, therefore have sought relief through tort law against those who manufacture these uniquely deadly products. With rare exceptions, however, these suits have been unsuccessful. Most courts have found that the conduct of gun manufacturers is not actionable under strict product liability doctrine, negligence, or the law of abnormally dangerous activities. This Article argues that courts have been too reluctant to apply tort liability to gun manufacturers. It is possible and necessary, the authors demonstrate, to fashion a rule of liability that will call irresponsible gun manufacturers to account, and that doing so will not amount to absolute liability against the gun industry. Drawing theoretical support for their position from central pillars of tort law, the authors offer a test for judging whether a class of guns should be considered defectively designed. Such a determination should hinge on whether the impugned gun is a "manifestly unreasonable" design. This concept is recognized in the Third Restatement of Torts, but too narrowly defined there. The authors flesh out the concept by reworking the factors for abnormally dangerous activities to make them more directly applicable to the complex array of design and marketing decisions that gun manufacturers make. Through a series of illustrations, they then apply this test to different types of guns and show how the test supports liability for certain egregious practices, but not for some other practices. In addition, the authors recommend that claims for negligent marketing be allowed to supplement the design claims in appropriate cases.