I am trying to find information about a Union Machine Company double Barrel shotgun with external hammers.?

Answer 1

Here is a link to their website

http://www.unionmachine.com/pages/about.html

You may have to call and ask them about the shotgun.

Also take a look at

http://www.thehighroad.org/showthread.php?t=199785

There are a lot more references if you search for union machine shotgun on the web.