Here you will find helpful information regarding the legal nature of spud guns or potato cannons propelled by a combustible fuel. Please read as it may be helpful to you in the future.
As defined in section 921(a) (3) of Title 18, United States Code (USC) the term Fire Arm means:
(A) 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;
(B) the frame or receiver of any such weapon;
(C) any firearm muffler or firearm silencer; or
(D) 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 an 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
Curtis H. A. Bartlett Acting Chief, Firearms Technology Branch
The information above is an excerpt of a letter that can be found here. http://www.spudfiles.com/forums/viewtopic.php?p=13324#13324
The letter was a reply from the Department of the Treasury in request for information on the status of potato guns as it pertains to firearms status. The letter was posted on 4/4/2006 by user PCGUY on an open forum at www.spudfiles.com.
Please use extreme caution and do not use other forms of fuel other than hair spray or deodorant, use ammunition other than potatoes, or fire in an unsafe environment. For more information...visit the How To, Faqs, or the Disclaimer section of SpudGunExtreme.
You can read about the affects of what could happen due to misuse of this product here. http://www.ksfy.com/news/local/9523117.html