The Breech Loaded Paintall “Shotgun”

Although this isn’t the first pneumatic air cannon to be featured on HAD, this “paintball shotgun” is certainly one of the coolest.  While most air cannons have little practical use besides looking awesome and being cool to play with, this cannon, according to it’s maker, has actually been used successfully in actual paintball competition.

The system works by preloading a sabot full of paintballs into a section of barrel that can be removed.  The barrel is then slid forward and the sabot/barrel section is then inserted and the gun is loaded.  This configuration is known as a “floating barrel” and seems to work quite well.

The author is quick to point out that this device is not designed to be used against human competitors, but against tanks and such in scenario games. Used properly or not, we can’t vouch for the safety of this device.  One should take extra caution when working with CO2 tanks as they can reach a maximum pressure in the thousands of PSI.

For other pneumatic cannon ideas, check out this other bolt-action miniature potato gun or this “water blob launcher”.

14 thoughts on “The Breech Loaded Paintall “Shotgun”

  1. “The cannon itself is made mostly of PVC pipe.”

    Might as well remove all of the red words and put a single one on it labeling this thing a bomb.

    Not a very violent one – but PLEASE STOP USING PVC WITH COMPRESSED AIR.


    Especially not with a CO2 source. Yes, it is regulated down but regulators can fail. And so does PVC – rather violently and catastrophically. Even with small scratches or just age.

    DO NOT USE PVC WITH COMPRESSED AIR. If you MUST use a polymer, use carbon fiber.

    1. You’re not making much sense. The regulators fail closed, and PVC is rated to 120psi. Unlike combustion guns, there is no peak that will ever exceed 120psi. The gun is safe. The PVC won’t even be exposed to a moderate temperature difference.

  2. I tried this years ago with a regular potato canon and found that the paint balls are almost always ripped apart before exiting the barrel due to friction with the sidewalls of the muzzle ( a potato was used as a sabot).

    The only way to prevent this was to load the ‘shot’ with a cup (or wad if you’re familiar with reloading shotgun shells) made from aluminum foil. I could get about a 12″ spread at 50′. Load size was limited as too much paintballs would actually crush from the sudden acceleration.

  3. I’ve made a few air cannons myself and I’ve always done a few things to make them safer:

    – wrap tanks in several layers of strapping tape (the fiber reinforced type)
    – keep 50% safety factor on handheld firings
    – use remote firing system on high-pressure launches
    – follow assembly procedure using rated fittings

    And most importantly, DON’T USE CO2 if you’re going to do this. PVC becomes brittle as it cools, and the decompressing CO2 isn’t helping at all. I’ve only ever used an air compressor or bike pump.

  4. I’ve never posted here, but I thought this to be worthy to be brought up. A “floating barrel” refers to a rifle or shotgun that is completely free from contact from the stock. Not the example in which this term is used. This is breech load. And I’ve only used combustion in PVC. Probably not the smartest, but definitely the cheapest. 2 bucks for a can of aquanet at the wally world.

  5. Lol saw this about 4 years ago. Look into using the spudtech “supa” valves. They are a much more efficient approach to this type of cannon and also reduce the fittings needed to close the loop. And they’re true machined piston valves that last longer and dump more air than conventional diaphragm based valves.

  6. *sigh*

    Is it just me or was the resivoir just PVC? Or was it steel? Please tell me it was steel. You NEVER use C02 in PVC unless the only PVC to come into contact with the gas is the barrel.

    @HaD: “While most air cannons have little practical use besides looking awesome and being cool to play with, this cannon, according to it’s maker, has actually been used successfully in actual paintball competition.” – Incorrect. Do some research.

    Air cannons are vastly popular in scenario / woodsball / concept paintball competitions & games, so much so that you can find them in armored tanks (actual tanks), down to UTG-style units.

    In fact there’s an entire web community dedicated to this topic:

    It’s like HaD authors are just repeater-bots or something. Link in .. Link post. No basic research, especially after the many, many posts on this particular topic with the hundreds of comments by experienced builders..

    Been building them for about 15 years myself. The unit featured here has a nice compact look.. it’s not the worst safety-minded build I’ve seen on here, so props for that. The build looks extremely old (the website cites first use at around 2000, with subsequent redesign since).

    @aEx155: Have you ever actually seen fiber-wrapped PVC be any less dangerous than non-fiber wrapped PVC? It’s like putting duct-tape on an M80. Good luck with that.

  7. The failure mode of rigid thermoplastic piping under these use conditions will be very dramatic. The rapid release of the pressure build-up associated with the combustion gases can result in the instantaneous rupture of the pipe wall and/or attached components. This will result in shards of plastic (shrapnel) rapidly escaping at high velocity.
    Temperatures created as the result of the ignition of flammable substances can quickly exceed the thermal properties of the piping, thereby greatly reducing its physical properties and making it more susceptible to failure.
    Shock loads associated with the combustion of the flammable substance can quickly exceed the design capabilities of the plastic piping.
    The sudden pressure rise associated with combustion can quickly exceed the pressure bearing capacity of the piping.
    Chemical compatibility issues with certain flammable substances can cause stress cracking and premature failure of the plastic.
    Warning! The use of plastic piping in these types of devices can result in severe bodily injury or death.

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