Build-it-Yourself Air Cannon Plans

Air Cannons, Are They Legal?

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Are Pneumatic Launchers, Potato Guns, and other Air Cannons Legal?

Depending on the country that you live in, there are differences in the laws on air guns. Below is the determination for the United States. For other countries visit the Wikipedia page on air gun laws.

Here is a letter that was sent to the Bureau of Alcohol, Tobacco and Firearms - Department of treasury.

This letter is referring to 'combustion spud guns.'

In the letter they state that these 'devices' (combustion or pneumatic) are legal, however you must check with your local law enforcement authorities because it may not be legal in your county.

Law Abiding? The Legality Of Air Cannons...

Just some advice: If you do encounter a law enforcement officer, don't argue with them. Just explain it uses air to launch things such as water balloons or potatoes. Give them a little demonstration - most likely they will start to crack up and find it very humorous.

Bureau of Alcohol, Tobacco and FirearmsHere is the letter:

Bureau of Alcohol, Tobacco and Firearms
Washington, DC 20226
Sep 12 1995 3311.4

City, State Zip


This refers to your letter of August 18, 1995, in which you ask about
the legality of a device known as the "Spud Gun."

These subject devices are generally constructed from PVC tubing and
fittings and are designed to launch a muzzle loaded potato using aerosol hair spray or other type of propellant. Ignition is by means of some type of "spark" igniter.

The Bureau has previously examined devices known as "Spud Guns, Potato Guns, or Spudzookas" and have determined that such devices, in and of themselves, are not firearms as defined in Title 18 United States Code (U.S.C.), Chapter 44, S 921(a)(3) or 26 U.S.C., Chapter 53, S 5845.

However, any similar devices which can be determined to be weapons by reason of their design construction, intended use, actual use,
ammunition or other factors may meet the definition of a firearm under
Title 18 or 26 U.S.C.

We suggest that you contact your State and local law enforcement
authorities concerning possession of such devices.

We trust that the foregoing has been responsive to your inquiry. If we
may be of further assistance please contact us.

Sincerely yours,

Edward M. Owen, Jr.
Chief, Firearms Technology Branch

Secondary Letter On Air Cannon Legality

Bureau of Alcohol, Tobacco and FirearmsATF -- Yes, they are legal.

Department of the Treasury
Bureau of Alcohol, Tobacco, and Firearms
Washington, DC 20226

As defined in section 921(a) (3) of Title 18, United States Code (USC) the term "firearm" means:

  1. any weapon (including a starter gun) which will or is designed to or may readily be converted to expel a projectile by the action of an explosive;
  2. the frame or receiver of any such weapon;
  3. any firearm muffler or firearm silencer; or
  4. any destructive device. Such term does not include an antique firearm.

As defined in 26 USC subsection 5845(f) (2) the term destructive device includes any type of weapon by whatever name known which will, or which may readily be converted to, expel a projectile by the action of an explosive or other propellant, the barrel or barrels of which have a bore of more than one-half inch in diameter, except a shotgun or shotgun shell which the Secretary or his delegate finds is generally recognized as particularly suitable for sporting purposes; and (3) any combination of parts either designed or intended for use in converting any device into a destructive device as defined in subparagraphs (1) and (2) and from which a destructive device may be readily assembled. The term 'destructive device' shall not include any device which is neither designed nor redesigned for use as a weapon; any device, although originally designed for use as a weapon, which is redesigned for use as a signaling, pyrotechnic, line throwing, safety, or similar device; surplus ordnance sold, loaned, or given by the Secretary of the Army pursuant to the provisions of section 4684(2), 4685, or 4686 of title 10 of the USC; or any other device which the Secretary of the Treasury or his delegate finds is not likely to be used as a weapon, or is an antique or is a rifle which the owner intends to use solely for sporting purposes.

It is unlawful for anyone to make or possess a destructive device which is not registered in accordance with the provisions of the National Firearms Act.

We have previously examined that certain muzzle loading devices known as "potato guns." These potato guns are constructed from PVC plastic tubing. They use hair spray or a similar aerosol substance for a propellant, and have some type of spark igniter. We have determined that these devices, as described, are not firearms provided that they are used solely for launching potatoes for recreational purposes. However, any such devices which are used as weapons or used to launch other forms of projectiles may be firearms and destructive devices as defined.

Bureau of Alcohol, Tobacco, and Firearms
Firearms Technology Branch, Room 6450
650 Massachusetts Avenue NW
Washington, DC 20226

Sincerely yours,

Curtis H. A. Bartlett Acting Chief, Firearms Technology Branch