Potato Guns

SayUncle took me back more than a few years with this post on Backyard Ballistics.


My friend Brad posing with the potato cannon we built more than ten years ago in New Hampshire. We’re all fatter and have less hair today. It could launch a spud a good 300 yards. Somewhere, I still have it, although it’s been shortened because it was too long to get back into the trunk for the drive home.

I had no idea, actually, that I could have been arrested driving that thing home. It’s a firearm both in Massachusetts and in New Jersey, and I did not have a license for either of those states. Moreover, because it’s not a firearm under federal law, I couldn’t claim FOPA. We carried with us a letter from the ATF saying it wasn’t a firearm, but didn’t realize that didn’t matter. State definitions vary.

Things you do when you’re a dumb college kid and assume you live in a free country where silly things like the constitution mean something.

7 thoughts on “Potato Guns”

  1. How does it “charge”? I’ve seen some that use bicycle pumps. (Or is it a combustion launcher?)

    I’m surprised anarchists don’t use these things to launch molotov cocktails against “The Man”.

  2. We used hairspray. Aquanet is the hairspray of choice. Basically you want something that uses a flammable gas as the aerosol. The gas plus combustion of the alcohol in the hairspray drives the potato pretty decently. You use a grill igniter as a trigger. Basically the process is this.

    1. Cut potato to the size of the muzzle such that it makes a tight seal.
    2. Ram potato down to the end of the barrel.
    3. Unscrew breech cap, and with the barrel pointed downwards in a safe direction, spray in the aquanet. A two to three second spray is sufficient.
    4. Replace breech cap ASAP after you finish spraying.
    5. Point in a safe direction and hit the grill igniter.

    I will fire with enough force to seriously injure or kill someone, so be careful. The hair spray also tends to gum up the cap, so make sure you wash the threads off when you’re finished. I’ve heard stories of people using gasoline, propane, and other propellants, but I would be careful. If you overpressure the PVC, you’ll be in a world of hurt. Aqua net worked for me.

  3. I’ve heard that WD40 is also a good choice as a “charge”, since it doubles as a cap lubricant, thus avoiding the trouble brought about by AquaNet.

    Another thing to be careful about is to let the chamber air out when you’re done. Not all of the gas is ignited by the grill lighter, so if you close the cap, wait a few hours and then hit the lighter button again, the lingering gas will ignite.

  4. Thats not a potato gun… Try an egg gun that could launch an egg much further.. and sometimes even unbroken. I’m going to have to hunt for pictures….

    It ran on strictly air pressure, so i don’t think it qualified as any type of a firearm. I really need to find pictures…

  5. That would still be a firearm in New Jersey, which means you need an FID to possess one, and you can do serious time for having one without a license. No FOPA exception, because it’s not a firearm under federal definitions.

  6. Well, i’m not in new jersey. And we were on private property (a boy scout camp) with it ;~)

  7. My spud gun is also a firearm under Arizona law (anything that shoots a projectile via expanding gases), but not Federal.

    If I want to take it on a plane with me I would need a large lockable case for it & I would have to store my ammunition (bag of potatoes) in a separate bag. ;)

    I use a can of butane gas in my spud gun that I got at a marine store (used for portable heaters I believe) – launches potatoes a very long distance with no gummy residue. Tons of fun for all.

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