Roy C. McHenry was a Special Agent with the Bureau Of Investigation (later named the FBI) from 1917 - 1920. Upon leaving he went into law practice in Binghamton, New York.
During the 1950's, McHenry wrote an article for the Retired Agent's Society magazine, "The Grapevine," and reveals his recollections of Agents having firearms in the Bureau in 1917, long before any Federal legislation.
In 1945, McHenry along with Walter S. Roper, wrote "Smith And Wesson Hand Guns".
Read the accounts of a 1917 GMan by clicking here. (The article is in .jpg image format and you should be able to download and save it for later reading.)
(c) Courtesy "Grapevine" Magazine, June-July 1955