On Fri, 21 Mar 2014 15:30:59 -0400, wrote:

I made this gatling gun for ping pong balls that runs off a vacuum
cleaner

http://gfretwell.com/ftp/gatping%20gun.wmv

Is registered with ATFE?

"...Bureau of Alcohol, Tobacco, Firearms and Explosives Firearms
Technology Branch has deemed “Chore Boy copper cleaning pads, along
with fiberglass insulation,” a firearm, subject to registration and a
$200 transfer tax, an official letter obtained recently by Gun Rights
Examiner reveals. The response to an attorney inquiry by John R.
Spencer, Chief, Firearms Technology Branch, offers one of the more
creatively restrictive assessments since ATF declared a shoestring to
be a machinegun."

"...(Former ATF official Robert E. Sanders) noted that ATF once issued
a letter ruling saying a 14-inch shoestring was a machine gun because
it could be used to convert a semi-automatic rifle into an automatic
weapon. The letter was later rescinded."

G