Bowling ball cannon / mortar: legal?

T

TXAZ

New member
My kids (adults) saw a "bowling ball cannon" and wanted to build one. It appears to be legal if you only use black powder. If you have built one or have looked into this in detail, any insight to the safety, legal issues or other concerns?
 
They'd better be well-heeled and willing to construct it right. You're talking about a 12 - 14" ball. Take a look at Civil War pictures of 13" mortars. They were HUGE, Heavy, and very difficult to transport.

They're that big and heavy for one reason - so they won't blow up when lobbing that big a projectile.

IIRC, at Ft. Ticonderoga 25 or so years ago, they had a Coehorn mortar that they used to launch pop cans full of cement. Only used about a shotshell's worth of Black Powder. Perhaps they should start with something like that:cool:
 
If you do build one, can you video the firing of it and post it? I'd love to see what that would look like......

I imagine if you fired something like that at night, it'd look like Hiroshima!
 
I've seen videos of these bowling ball cannons. Usually they use the type of tank that you would use for acetylene or oxygen. They cut off the bottom, and cap off the top where the regulator goes. I see the comparison to civil war era mortars, but a bowling ball isn't all that heavy, and a tank is built to handle some pressure.
 
mortars

The advice to start small is good.
I have two golf ball mortars that I use with my grandkids. Small enough to transport and still provide a safe means to have some fun and pop golf balls a few hundred yards.
About making mortars....lots of mortars are really under safe spec. The standard is to have a wall thickness three times the bore diameter.....hence the very heavy mortars of the CW.
At least, the breech/powder chamber should follow this spec.
Yes, people do use cut off gas cylinders.......just because you can, doesn't mean that you should.
My little mortar - note the thickness of the breech plug/!powder chamber:


 
We made tennis ball cannons out of the ball tubes (three) and Zippo fuel when I was in college - it would launch a tennis over 100' across a street or field
 
I met a US Park Police Lt who, as a teenager in college, worked as a Civil War renactor doing mortar shoots. They'd use very little powder and would shoot the ball no more than 100 yds. One day they thought why not try a whole pound? It launched out of sight. They formed a skirmish line and walked at least a mile to find it. Luckily no one and no car had been smashed by it. After that the Park Service stopped the mortar demonstrations.
 
Most gas cylinders are made for 2 to 5 thousand psi working pressures.
Not really all that much as compared to guns and cannon.
Some cylinders aren't even made of steel, but rather aluminum and fiberglass.
Just a thought.
 
If I may offer some safety advice from the fireworks industry, fireworks mortars are now constructed using HPDE pipe. It is very strong and when it fails due to overpressure, it does so exceedingly gracefully. It bursts without throwing off shrapnel that can cause injury to more distant spectators. Typically the bottom is of the mortar tube on the ground or on a rack that is in contact with the ground and the bottom of the mortar tube is plugged with a wooden fitted plug.

Fireworks shells typically have lift charges under them that are black powder, with volumes of maybe 8 ounces for small (4") shells and increasing as the shell size increases. The lift charges are calculated to send the shell up about 100' for each inch of shell diameter. Fireworks shells are not heavy and sized to be a loose fit in the mortar.

So folks thinking of making a small cannon for "fun" might start by purchasing some HDPE pipe. Aluminum, steel, and even PVC sends out very dangerous shrapnel when they fail.

As to the legality, in Massachusetts you have to get a "cannon license". A friend who was involved in Revolutionary War reenactments has one. In NH, well its the Live Free or Die state.

Best of luck,

Wes
 
I saw one fired at a SoCal range several years ago.

IIRC, the tube wasn't very long, say 15"-20" and wasn't more than 75lbs.

It didn't look like much, so I wasn't expecting much: I was wrong.

With a little black powder, it launched that bowling ball up and away until it turned into a dot, then the dot disappeared over a ridge. No idea how far away it landed.
 
The pressures inside a cannon firing a bowling ball, would seem to be far greater than firing light weight, loose fitting firework projectiles.
Would HDPE really be safe for a real cannon?
 
In a bowling ball mortar, the powder cup is surrounded by at least 2" of steel in all directions (except one). The tube really just acts as a guide to direct the ball for the first few inches and doesn't really hold any pressure. At least that's how they're supposed to be designed.
 
Search youtube for "Bowling Ball Cannon American Guns".
Your looking for the one posted by Discovery Networks.
They're using a typical CO2 tank with great results, study the design, pay particular attention to the 39 second mark where it shows how the top of the cylinder is modified to hold the fuse.
 
I once saw an interesting demonstration of a gasoline-powered mortar that would launch full beer or soda cans a couple of hundred yards; this fellow would pour a teaspoon of gasoline into the tube, drop a can on top of it, then press a button to complete a circuit through a spark-plug in a fitting he had welded into the bottom of the mortar, and it would send those cans into next week.
 
Thanks. While this looks interesting, it's pretty clear putting enough pressure to lift a 16 lb bowling ball 300' in altitude and distance could have serious downsides (like death) for someone who doesn't know how strong a vessel is required to prevent Fire and EMS response.
 
Ah... dont give up that easily.

If the correct (slower burning) powder is used, and there is a bit of a gap between the ball and cylinder, you should be fine if you use a proper "industry standard" steel tank.
This works because all of that pressure is spread across (burn) time and large amounts of square inches, plus the blow-by from the loose fitting ball.

Start with 12 to 14 pound balls... nobody said 16 pounders are required.
Just incrementally bump up your powder charge til your happy with the distance, you know.. somewhere short of dangerous :D

Remember tho... dont weld anything to the cylinder, that'll weaken it.
 
I think it was an old TV show called "Thats Incredible" where they showed a man using a bowling ball mortar to knock over old grain silos. He would shoot them several times till he cut them down.
 
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