So in its place, he launched his initial tech enterprise, which built him a millionaire by age 28. Then he commenced yet another company - and a further - amassing tens of millions and then billions of bucks in prosperity together the way. Hemenway, David. "The Myth of Millions of Annual Self-Defense Gun Uses." Chance. Krouse, William J. "Gun Control Legislation." Congressional Research Service. Koper, Christopher S.