So as an alternative, he launched his initially tech enterprise, which made him a millionaire by age 28. Then he started out yet another business - and an additional - amassing tens of millions and then billions of pounds in wealth alongside 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.