The year FBI agents could carry a gun?

Agents of the FBI were authorized to carry firearms after the passage of the June 1934 Crime Bill, which also included the 1934 National Firearms Act, restricting the possession, sale and transfer of machine guns, short barrel rifles, shotguns, silencers and destructive devices. This was in response to the "criminal use" of full auto and other weapons during the 1932-1934 crime wave across America.