Breach Loaded Air Cannon

Posted on April 22, 2019 by PukinDog

The following are pictures and component descriptions of the Paintball air cannon that I built and have used very successfully. This article is for informational purposes only. As far as I know this is the first Paintball cannon of its kind. It is basically an air powered potato cannon with a few twists added to make it more suitable for recreational paintball.

BREECH LOADED

Release the latch, slide the barrel forward, remove the spent cylinder

This system uses a floating barrel, that is to say that the barrel is slid forward through a set of collars to release a short section of barrel from between a set of couplers. This short section of barrel is then replaced with another section that has been pre-packed with paintballs in a cardboard sabot. The barrel is then slid back, closing the couplers on the new loaded barrel section. A clamp that reaches from one coupler to the other is then latched and locked to secure the preload and floating barrel in place. The whole process takes 10 to 15 seconds to perform.

Sabot assembly and loading

The Sabot – I use a sabot made from cardboard toilet paper roll cores and Dixie cups. I have found that this delivery system dramatically improves the pattern of the paintballs over a much greater distance. I believe this is because the paintballs do not contact the barrel (keeping the balls from spinning) and it keeps them in a cluster until the have fully exited the gun (keeping them from pushing each other out of the way as they exit).

The sabot itself consists of one toilet paper roll core split in two and slid into one Dixie cup that is modified to fit into the barrel piece. The very bottom of another cup is taped to the back of the sabot to form a cup seal. The sabot is then slid into the shell and 24 paintballs are placed inside. One more cup is then slit in two and placed over the front of the sabot to keep the paintballs in place until fired. After the sabot leaves the gun it basically splits apart and allows the paintballs to go on their way. This all gives me a pattern spread of 6 to 10 feet at 40 yards.

ELECTRO PNEUMATIC

RainBird valve and battery pack Spyder grip frame and pushbutton trigger

The firing mechanism for this cannon consists of a RainBird electric sprinkler system valve, two 9-volt batteries and a momentary pushbutton (the RainBird valve has been commonly used in airpowered paintball and potato canons). The valve goes between the low-pressure reservoir and the barrel assembly. The power supply consists of two 9-volt batteries wired in series to produce 18-volts (the RainBird valve is rated for 24 volts but works just fine with 18). It’s triggered by a momentary pushbutton switch mounted in a gutted out plastic grip assembly from a Spyder paintball gun. Pushing the button provides 18 volts to the valve, which opens allowing the pressurized Co2 to pass from the reservoir to the barrel.

CONSTANT AIR

Twelve-ounce tank, Palmer regulator and pressure gage

Air pressure is provided by a 12 ounce, anti siphon, paintball Co2 tank. The Co2 tank is threaded into a Palmer Stabilizer regulator adjusted to bring the pressure down to 120 psi (the RainBird valve is pressure rated at 120 psi). This lower pressure Co2 is fed into the low-pressure reservoir that feeds the valve. A pressure gauge is mounted in the line between the Stabilizer and the reservoir to insure that the pressure does not exceed the rated limits. WARNING! CO2 is capable of producing pressures in excess of 2000 psi. This kind of pressure is very dangerous. It is CRITICAL that a good regulator be used, and the pressure monitored to insure that it does not exceed ratings. An-anti siphon Co2 tank is recommended the keep liquid Co2 from freezing up the regulator and causing over pressurization.

Note: I use a Co2 tank with an on/off valve. Though technically you can leave the Co2 tank on full time, I recommend that the low pressure chamber not be filled until you’re ready to fire the gun. This minimizes the risk of regulator failure or the possibility of falling on the gun and breaking open the pressurized chamber. THINK SAFETY FIRST!

CANNON

The cannon itself is made mostly of PVC pipe. The low-pressure reservoir is 2-inch PVC, the barrel and pre-loads are 1.5-inch PVC. I found that the smaller barrel achieved higher, more consistent velocities. Connecting the reservoir to the barrel is a standard .75-inch, U-turn RainBird sprinkler valve. The barrel slips through two couplers that have been reamed out to allow to barrel to move somewhat freely forward. Attached to the back of the barrel and the outlet of the valve are couplers that have been reamed just enough to allow the pre-loaded barrel piece to fit snugly between the two when the barrel is pulled back. The couplers are held fast by a spring-loaded clamp that stretches between the barrel and the valve. The input from Co2 tank and the reservoir is made of small brass pipes and fittings common to any good hardware store.

Fired from 25 feet The BECC got its first serious workout at the Aurora Borealis 24 hr. scenario game at Wayne’s World, Ocala Fla. in April, 2000 . Out of 14 shots fired I eliminated 12 enemy tanks. Not too shabby.

Over the past couple of years, many commercial paintball fields have outlawed the use of multi-ball air cannons such as the BECC, and have instead opted to go with soft projectiles such as nerf rockets. Despite it’s 1.5 inch inside barrel diameter, the BECC is able to use commonly found finned nerf footballs. The footballs are a tight fit in the pre-load chambers of the BECC, but with about 120 psi the little footballs fire amazingly straight.
There are no drawn plans or parts list for the BECC. The gun was pieced together in a trial and error process, and is still subject to further modification. For larger detailed pictures of the latest version of the BECC, click on any of the following three pictures.

Download the 5 second .mpg video of a 24 paintball shot (489 KB) by clicking here

Click on the picture to download a short .avi video of the BECC targeting a small folding table with a nerf rocket.

This cannon is designed to be used against armored vehicles and bunkers in scenario games and not (for obvious reasons) against other players unless used in a long range, mortar fire fashion. I hope this information is useful.
Play safe and have fun.

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Breach Loaded Air Cannon

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