One thing that is great about America is garages. Inside those garages the inveterate American tinkerer is alive and well, and in this case, cranking out Gatling guns (pun intended). Buying a Gatling gun is incredibly expensive, so the patrons of Gatling Gun Forums focus on building their own guns, and there is plenty of helpful info in this regard. The most interesting section for me is the Progress section, where builders show the state of their build at the moment. Some pretty nice work.
Contributor my65pan's progress on .22 Gatling
Contributor Bruski's Gatling carriage
Contributor steampunk's 9mm blank firing Gatling
Contributor jftool's .22 Gatling
Contributor jarhead jim's 12 gauge 6 barrel Gatling