Jingle gun / Cannon question

woodchopper

woodchopper

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I'm thinking I need to build a big jingle gun, and looking at some pipe 2" XXS has in ID of about 1.5" (37-38mm ish) and I thin that would make a great barrel, 9 lbs/foot so its going to be heavy, and I want to make it breach loading (similar in size to 37x94R)

My question to the cannon guys is at what point is it not considered a 'long arm' and becomes a breach loading cannon / destructive device ?? is it 40mm??

I figured I'de ask here where the cannon experts reside rather then in the gunsmithing forum.
 
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There are no regulations on cannons. Just listening to your plans, you're an accident waiting to happen. You had better not be the cause of regulations
being issued against responsible artillerymen. Buy Matt Switlick's book "The complete Cannonneer" before proceeding any further.
 
My take on the "long gun -cannon" question is that if it is percussion or primer fired it is a long gun, regardless of cal. ...if it is quick match or fuse fired it is a cannon....cannon =non firearms act controlled.

Your first point on the size of your "tube" would concern me. 2" od and 1.5" id only leaves .250 actual steel thickness. unless your tube is of a known very hi tensile grade of steel (even then ?????), personally I would be very cautious as to charge size and projectile weight.

not trying to discourage you as cannoneering is very enjoyable and, while I'm by far not a expert at it , I have read a lot on the subject and one thing I have gained from that is that oftentimes you can't learn from your mistakes...the first mistake is often the last.

Wood Chopper check your PM's
 
2" xxs pipe is 2.375 OD x .436 wall. There's a little more meat to the wall than 1/2" . Running it through the barlow's formula calculator at http://www.aerocomfittings.com/barlows.html using 30,000 psi (I'm assuming black powder) would mean your material would need a yield strength of 81,708 psi to just barely contain the pressure with no safety margin. Of course that's not taking into account the strength at the weld, either.

If you're in an area that does oilfield or aerospace work, look for a gundrilling shop. They should be able to make a tube for you in whatever size you desire.
 
This sounded good so I did a surprisingly simple google search on "xxs pipe pressure rating" and found this;

http://www.kalhour.ae/downloads/psi_chart_as_per_pipe_wt.pdf

Looks like this won't work for anything serious since the burst strength for 2" XXS is only 22,100. That isn't enough to give any sort of safety factor even for a golf ball cannon.

0.43" sounds like a lot of wall but as the pipe grows in bore the need for the wall to thicken up grows exponentially. Which is why we see really thick walls on big bore guns.
 
BCRider said:
This sounded good so I did a surprisingly simple google search on "xxs pipe pressure rating" and found this;

http://www.kalhour.ae/downloads/psi_chart_as_per_pipe_wt.pdf

Looks like this won't work for anything serious since the burst strength for 2" XXS is only 22,100. That isn't enough to give any sort of safety factor even for a golf ball cannon.

0.43" sounds like a lot of wall but as the pipe grows in bore the need for the wall to thicken up grows exponentially. Which is why we see really thick walls on big bore guns.
Click to expand...

Actually, it's even worse than that, since you don't want your barrel to spend it's entire (short) life at the ragged edge of its strength. The working pressure listed for schedule XXS 2" is 6300psi, which gives you a minimally reasonable 3.5x safety factor. Designing without a safety factor means the smallest imperfection can easily become where the barrel starts to come apart.

I'd love to make a jingle (djingal?, jingal?) myself, but i'd want to get more than a proofing shot out of it.

Woodchopper, since you're in Edmonton (couldn't see that last night on the mobile site), try talking to gambit or ck5. I don't know them, just know of them, but I believe they both do gundrilling.

J
 
I'm surprised it took this long for the thread to re-surface.

I did a bit of research on XXS pipe and with a burst strenght of 20K psi is way too low to mess around with for anything serious.

I would need a much thicker sidewall.

I'm really not interested in blowing myself up.
 
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