Incredibly powerful spudguns

I did not realize that physics would allow spudguns to achieve the level of power achieved by Sureshot’s guns cannons.


Most of Sureshots guns operate by injecting Methylacetylene-Propadiene gas into an expantion chamber and then igniting it.

The BL-415, which uses the Methylacetylene-Propadiene gas system, can generate up to 450 ft/lbs of muzzle energy. That is around the same muzzle energy of a .45 ACP round!

For comparison, the FN 303 less-lethal launcher generates just 16-24 ft/lbs of energy. The most powerful “less” lethal 12 gauge, 37mm and 40mm rounds top at just over 100 ft/lbs. The Sureshot guns could not be considered less-lethal.


The 60″ long tennis ball sized barrel of the BL-525 can generate 2000+ fl/lbs of energy if loaded with a proprietary 4090 grain UHMW/steel projectile. That is more energy than a 6.8mm Remington SPC cartridge!

Impressive? You have seen nothing yet … The below video shows a proof of concept developed for a Mexican defense contractor. It fires a 6790 grain projectile and generates 3000 ft/lbs of muzzle energy!!! That is more than a .308 Winchester!

Check the legality of spudguns in your state or country before you embark on building one.

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • viper5552

    imagine if that was equipped with HEAT or HE-FRAG rounds instead of steel shot, it would be like a silent recoilless rifle!

    • viper5552, I did not think of that!



  • Jim

    I did not think I’d ever be so excited to see a potato gun! So much for the old PVC ones we used to make…

  • spudfiles
    • spudfiles, very interesting!

  • Pete

    Next step, rifle the barrel?

    The power and accuracy are amazing at 100 yards!

  • Josh

    You seem to be equating muzzle energy with a weapon’s level of lethality. While there is certainly a correlation, consider that 65 ft/lbs is considered adequate energy for an arrow to hunt large game (according to some websites about African safaris, this is minimum sufficient for hunting buffalo and giraffe). Conversely, that 3,000 ft/lbs of energy you mentioned (more than a .308 Winchester) would be generated by a 3,500 pound car traveling 5 miles per hour. I would rather be struck by the car than the arrow!

    My point is simply that there is much more than kinetic energy at work in determining whether something is lethal or not. A potato may have 450 ft/lbs of energy, but that energy will dissipate upon impact due to the physical properties of the potato (i.e., it’s soft). A water balloon traveling at the same speed and of the same mass would have an equal amount of energy as well, but would, of course, be even less dangerous than the potato.

    Muzzle energies are a good way to compare similar items, like bullets of the same or similar diameter, but can be misleading when comparing very dissimilar things.

    • Josh, sure, a freight train (with freight attached) moving at 1 foot / hour may be generating 3000 ft/lbs of energy. But we are not talking about a car, but a relatively small projectile that can penetrate steel. It would crush a human chest in.

      Regarding muzzle energy. Can you give me a link to an African safari that allows 65 ft/lbs? That is very irresponsible of them.

  • Matt Groom

    We made one years ago that used compressed air via an air compressor and propane from a small 16 oz propane cans. Air pressure would be set to 120 PSI (as per our gauge’s max reading!) and then released with a valve off of an air rifle that had a striker. Propane was pumped directly into the barrel behind a tennis ball generously lubricated with gasoline. Hit the striker on the valve, the compressed air would push the tennis ball down the barrel but as it passed a couple of wires connected to car (or boat) battery terminals, it would complete the circuit, igniting the gas. It had an impressive sound and the burning propane would ignite the tennis ball. We launched it off of my friend’s boat and at night you could see the burning tennis ball for about 1/4 mile. It was a lot of fun, but a lot of work to get everything working in concert, and it didn’t work 100%. Probably 80%. No where near this level of performance.

    • Matt, I have also played with them. Like you, reliability was a problem.

  • Carl

    Recoilless, but with recoil. 🙂 And it’s so portable! you only need one (1) forklift to mount it on!

  • will

    Yea and you only need a fork lift to transport and fire it.



  • Josh

    It appears that it’s not irresponsible, because that’s the reality of it. A 400 grain arrow at 250 fps (which is very realistic from what I’ve read) has about 56 ft/lbs of energy.

    There are many websites that list around 65 pounds. It looks like the energy they’re talking about on the first two websites here (the safari sites) is actually the energy of the bow, I suppose the draw weight. However, the arrow doesn’t pick up any energy from a source other than the bow, so the energy of the arrow should theoretically be no more than the energy that the bow has to begin with.

    Here are some sites

    I don’t think bowhunters would appreciate you calling them irresponsible for hunting with such low energy weapons. Man has been killing game with bows and arrows long before the invention of the firearm!

    • Josh, ah, you did not say bowhunting. Bow hunting is not the same as shooting with a rifle. It kills by internal hemorrhaging and requires the shooter to be close and to place the arrow through the lungs (boadside shot), then to track the animal to where it dies.

      I once saw a documentry about a Southern African tribe that requires young men to kill a lion with a spear before they can become men! I don’t have a problem with hunting with bow, spears, crossbows etc.

      Josh, I agree that things kill differently and that muzzle energy is only one factor.

  • Matt Groom

    I agree with Steve about arrows being something else entirely. Arrow are slicing (actually tearing) weapons, like spears or swords which cause shock thorough blood loss. Whereas firearms bullets are crushing or bludgeoning weapons more akin to a club or other blunt instrument which cause shock primarily through tissue damage. That’s because even very pointy bullets don’t slice, except when yawing. It’s more like a drill without flutes.

    It reminds me of the old saying: “Guns don’t kill people, shock induced by blunt force trauma kills people.”

  • SpudGun

    I’m just pleased to have my name in print. 🙂

    And now for the bad joke – if you do get hit by one of these potatoes, would you get treated by MASH?

    • SpudGun, LOL, bad joke but funny.

  • Josh


    “Josh, ah, you did not say bowhunting. Bow hunting is not the same as shooting with a rifle.”

    I said, and I quote, “65 ft/lbs is considered adequate energy for an arrow to hunt large game.” I assumed it was understood I meant an arrow launched from a bow, not an arrow fired from a rifle!

    I was just trying to discuss the (what I perceive as) misconception that kinetic energy is (almost) the only factor to consider regarding the “killing power” of a particular projectile/bullet/caliber.

    Your logical progression in the article went something like this:

    -The BL-415 generates up to 450 ft/lbs of muzzle energy.
    -The most powerful “less” lethal rounds top out at just over 100 ft/lbs.
    -The Sureshot guns could not be considered less-lethal.

    This reminds me of the logic questions on grad school application tests. The preceding is only logical if muzzle energy is the only factor in determining lethality.

    Forgive me, it’s been snowing pretty heavily out today and I’ve stayed inside with too much time on my hands! They are some pretty impressive looking potato guns, and I wouldn’t want to get hit with one, lethal or not.

    • Josh, my mistake. I did not read “arrow”.

  • Josh

    “Josh, sure, a freight train (with freight attached) moving at 1 foot / hour may be generating 3000 ft/lbs of energy.”

    I started thinking about this and wondered if that would be true. Turns out, it’s probably not. Turns out if you do the math on this it works out that you’d need a train weighing approximately 1.24 billions TONS. That works out to a train with more than 8 million cars, that would stretch more than 80,000 miles, or wrap around the equator more than 3 times.

    Just in case anyone besides me was wondering.

    • Josh, LOL, good job on the maths.

  • Greetings from Texas,
    I love this stuff. Every time my friend Butch and I mention a muzzle loading cannon my wife always brings up spud guns. When I showed her this today she asked if the cannon was still available.

    • Arthur, those are from their 2010 line up.

  • Thanks to everyone for checking out our cannons. We had a lot of fun developing these and even more fun putting 2″-3″ holes in various things.

    Here’s my two cents on the energy content and relative to this discussion. My ole man has a foam deer target for bow practice. The same broadheads he uses for hunting penetrate 7 inches in the foam target. This is the same setup he successfully takes deer with. Reluctantly he allowed me one shot with a BL-520 and our 2″ compound round. The compound round penetrated the same depth and still resides in the foam deer today.

    We have lots of cannons ready to ship for Christmas. Our ML-625e was the hot gift of this year.

    Sureshot Inc. /

  • D_Hall

    When most people think of spud guns they imagine punk teenagers with cans of hair spray and PVC pipe. Rest assured that there are those who take the hobby every bit as seriously as those in the firearms community with similar attention to detail, materials, etc. And yes, quite a few of them are undoubtedly lethal (and do not require a forklift to use).

    On a personal note, I’m personally finishing up a spud gun that should have a muzzle energy in excess of 1 *million* ft pounds.

    No, that one’s not shoulder fired. 😉

  • Josh

    Am I the only one that thinks the post by D_Hall sounds a little far-fetched?

  • D_Hall


    Let me put it this way… 19″ bore. 40′ long barrel.

  • Josh


    That’s an impressive looking device. In case you hadn’t noticed, I’m a fan of mathematics and physics, and my skepticism of a “spud gun” that generates 1 million ft/lbs of energy is based on my thoughts of the math and physics of it. You would have to launch a one-pound potato at about 5500 miles per hour. Or you could launch a bushel of spuds at the speed of sound to generate that energy (54 lbs of potatoes at 1089 fps/742 mph). Or

    In either case it seems likely that a spud, or a bushel of spuds, would isntantly turn to mashed potatoes when launched with forces necessary to obtain those velocities.

  • D_Hall

    As evidenced by the very gun that inspired this thread… At least in the spudding community, the term “spud gun” is generally more a reference to the techniques and technologies employed rather than the actual projectiles involved. You will find many many “spud guns” that have never actually had potatoes in them. Spudders will shoot just about any projectile that is consistent in manufacture and can be had for low cost. Common examples? Tennis balls. Golf balls. Ball bearings. I think it’s fair to say that I’m respected in the spud gun world, but I’ve never actually fired a potato from a gun (they’re too inconsistant for my tastes).

    All that said… I do intend on finding out if sack of spuds (with sabot, obviously) will survive my gun, but even if it doesn’t, I’ll just laugh. The gun wasn’t built for spuds. If it will shoot them, that’s just icing on the proverbial cake.

  • Josh


    It occurs to me that the term “spud gun” came about to describe the fairly innocent, and largely legal and unregulated devices used for launching potatoes in the backyard for fun. It seems though, that many of these devices have transcended the realm of “spud gun” and could fully qualify as a “destructive device” as described by 18 U.S.C. §921(a)(4)(B) by nearly any reasonable person’s assessment. Perhaps there’s a more appropriate name to describe them so as not to confuse them with the (mostly) innocent hobbyist potato gun.

    I think that continuing to refer to these (potentially) very dangerous devices as “spud guns” might lead to confusion and problems that could lead to regulation (or the attempt to regulate) all devices, with no distinction between highly engineered devices firing special projectiles and the PVC constructed, hair spray fueled launchers of root vegetables.

  • D_Hall

    And yet, “Punkin Chunkin” competitions are held nationwide and on national TV(*). I think if the ATF had any issues they’d have their “smoking gun” both literally and figuratively right there.

    (*) Note that the only difference between a “punkin cannon” and a “spud gun” is scale. There are those who’ve tried to call mine a punkin cannon, but I maintain that it’s a spud gun as it’s too big for punkins. 🙂

  • Josh

    A key difference there is the pumpkin cannons are designed for a regulated and recognized competition event. Also, I think the more likely real danger is in the very powerful portable devices capable of firing a potato, or something more damaging, with potentially deadly energies.

    Also noteworthy is that those pumpkin cannons (from what I’ve been able to ascertain) fire pumpkins at speeds which, along with the maximum allowable weight of 10 lbs/pumpkin, generate less than 20% of the energy you’re claiming to be able to reach. However, their goal isn’t firing a projectile with high energy.

    So, the purpose of the pumpkin cannon is to launch a pumpkin in a competition for a maximum distance. By contrast, your goal seems to be to construct a device with an enormous amount of muzzle energy. And for what purpose?

  • D_Hall

    Oh please, if all it takes to gain legitimacy is a regulated competition anyone could sponsor a competition for virtually anything. Just because somebody is offering a reward with conditions for an activity does not make that activity legal.

    And we’ll agree to disagree on the potential dangers. My personal feelings on the topic boil down to proximity to crowds…. And a large gun near an essentially uncontrolled/unprotected crowd (like those at a contest) is a recipe for disaster IMHO.

    By contrast, I’m not involved in any contest and my gun is a business venture. As flor safety/location, where I’ll be firing my gun I have a few thousand acres of unihabited land at my disposal. Surrounded by barbed wire. With armed guards. I’m not kidding. My gun may or may not work as advertised, but there’s effectively zero chance of anybody being hurt even if the thing just flat out blows up (firing systems are operated remotely).

    As for the purpose of my gun? It’s a laboratory tool. It’s purpose is the study of transonic impacts of aircraft flight recorders (ie, “black boxes”) and similar components. To study impacts at such speeds you must first attain those speeds. That these speeds involve high energies is simply a consequence of the laws of physics. If you find a way to accelerate black boxes to transonic speeds without involving high energies, please let me know as I’d like to say I debated a Nobel Prize winner.

  • Josh

    As I had said before, I think that the more realistic danger is from the portable devices capable of firing projectiles at potentially deadly speeds. As you’ve stated your device is for studying impacts of various components at high speeds; that’s a legitimate use, and far removed from these other “guns.”

    My opposition, or apprehension at least, to the subject of this thread is that those smaller devices seem to be inherently dangerous, and it seems that it would be extremely easy for someone to get hurt with them, accidentally or intentionally. On a sliding scale, those devices seem to fall much closer to the side of a “destructive device” or “offensive weapon” than they do to the side of a hobby device.

    Don’t take this to be directed at you or your work personally. Like I said, it’s impressive that you can build something so powerful. Likewise, the portable ones that are so powerful are also very impressive.

    I guess more than anything though I find part of this situation kind of funny. No doubt about it, these things can be dangerous (again, I’m talking specifically about the portable ones, the “big brothers” to the traditional potato gun). It also seems to me that the legality of these things is questionable, at the very least. With that in mind, I don’t think I would want to advertise too much the fact that I was in possession or manufacturing these devices. It seems to be begging for attention of the wrong sort. It certainly seems like less than a terrific idea to advertise how powerful they are, or how much more powerful they are than the most powerful less-than-lethal rounds used by law enforcement.

  • Brian

    The reason the Feds, and most states, don’t bother with “spudguns” is because they simply aren’t used for committing criminal acts. The worst thing LEOs have to worry about with 99.99999% of spudders is the occasional careless accidental impact on a house, or the rarer act of blowing windows out of abandoned buildings. As long as they aren’t being used for destructive purposes or in a flagrantly unsafe manner, most police simply don’t care about spudguns. Except for a very few, spudguns are simply too complicated, unwieldy, unreliable, weak, or simply impractical to use as a criminal tool.
    The only reasons any State or Fed lawmaker would get an unshakable hair up his butt about them would be if they are unusually stupid, or if someone in his district got hurt by on, or if they had a string of vandalism traced back to one.
    Local city laws are another matter, though. Most local city ordinances for spudguns come about because some city council moron gets annoyed by kids setting them off and making noise, not out of any real concern over safety.