How to blow up a cannon

[armorer77]

Hi guys , for the last few months I have been reading about mistakes , mishaps , and out right stupidity . This also seems to be a good time to test the wall = chamber rule . So I have decided to test one of my barrels to destruction . I am using my Parrot carbine . Chosen as the easiest to replace ,and the thinnest wall that I make,  and I have a spare due to a cancelled order . I bought a lb. of 4F BP today . This tube is intended to be shot with 300grs. of 1F BP and a 1lb lead ball , my  prototype has 15 full loads thru it with no signs of distress . I will post tomorrow afternoon with photos of the test . Wish me luck . I also have a large stack of cement blocks to sit behind and observe . Armorer77

[Spuddy]

This should be interesting.

[Cat Whisperer]

A thought.

If you start with a stiff charge and continue to increase it until failure, you will have found a known point of failure.  Then on the next opportunity, step down a level and repeat until failure.  THEN you have found a known load that will withstand X firings.  Back down several to many levels and you can fire more many more than X.

[armorer77]

This purely a test to destruction or til' I run out of powder  . I know my barrels will stand up to normal loads for longer than I will live . I normally shot 475  grs and 1lb. lead ball in my 12" Parrot and it is a hoot . Getting good hits at 100 yds. Gonna move the targets back after the test is over . Armorer77

[Cat Whisperer]

Have FUN and be SAFE!

Looking forward to the pix!

[KABAR2]

Armorer77,

Are you going to measure the diameter of the O.D. after each shot until destruction?

It would be interesting to see how much the metal has stretched before failure.

[RocklockI]

so the wall is at least as thick as the bore ?

sounds like a fun project . good luck .

[armorer77]

Bore is 1" wall is 1.125 . I will mic the OD after each shot . Armorer77

[GGaskill]

Are we placing bets?     I think he will run out of powder unless he uses double or triple shot.

[Victor3]

 I was just going to suggest we start a pool 

 I'll go with 1/2# of powder and 2 lead balls.

 

[Cat Whisperer]

The key to KABOOM is not the amount of powder, but the quality of the obstruction.  I.e.: it doesn't take much powder if the resistance of the obstruction is close to the strength of the material in the rest of the barrel.

[dan610324]

dont be so sure of that
when I was building a pair flintlock duelling pistols a long time ago I used 2 breachplugs in a barrel
one in each end, just to test the strength of the breach plug construction
I fired it with 8 gram ffg with a fuse
it just sound like a jet engine for a while while the built up pressure came out through the vent hole
no visible damages at all , but I didnt mic it before and after

[Boom J]

I think Ed has stated elswhere that he's using 1018 steel, and this is a relatively short barrel, so I wouldn't hold my breath waiting for this barrel to burst from a BP load.

[Cat Whisperer]

Mud is one of the materials recommended by the Army to destroy captured enemy artillery.

[dynomike]

Does anyone know of a chart that converts from oz. to grains or vica versa? I am going to shoot mine today w/ 2oz. cannon grade powder and 2lb lead ball w/ a sabot w/ 0.007 clearnce. I was wondering cause some people say grains and some say oz's.

[seacoastartillery]

     Dynomike,   for avoir, or more correctly, avoirdupois weight, which is used for weighing powder, just remember that there are 7,000 grains per pound, so divide by 16 oz. and you get 437.5 grains in each ounce (oz.). That's it.

     Sometimes the Troy Weight system used to weigh precious metals and gems is confused with the Avoirdupois system weights.  This is incorrect.  They are COMPLETELY separate and different.

                          Troy Weight

                 Unit                        Grains    Grams
Troy pound (12 troy ounces)         5,760    373.241 721 6
Troy ounce (20 pennyweights)    480    31.103 476 8


     Also, we would like to relate to armorer 77 our method for conducting similar tests.  We dig a 24" deep hole in the ground to contain all debris, should the tube being tested fail and put a looooong fuse on it and retire to a special 7,600 pound steel barricade built for us by General Motors Corp., the OLD GMC, a Suburban which is parked 50 yards away and BELOW the crown of the testing hill.  We never had a tube fail yet, but testing to destruction was never on the menu.  A standard three times service load of powder and two times shot weight is always used during these prototype tests.  This was one of the testing methodologies used during the War for Southern Independence.  Stay safe, Armorer 77, stay safe.

Regards,

Mike and Tracy

[subdjoe]

But a grain is a grain is a grain:  One of the earliest units of common measure and the smallest, it is a uniform unit in the avoirdupois, apothecaries’, and troy systems.

[armorer77]

Testing is finished for today . I reached 1000grs. with 4 1lb. lead balls before destroying my testing base . Pulled the heads off 2  3/8" carriage bolts putting an end to todays shooting . For the curious , measuring just ahead of the chamber reinforcement band . No noticible change . Total varience was +.0006 " Photos and movies to follow This evening . Armorer77

[subdjoe]

um...is that two each 3/8 inch carriage bolts or 2 3/8" carriage bolts?   

[Double D]

Here is a handy piece of shareware, that I think Cat Whisperer posted several years ago.

http://joshmadison.com/software/convert-for-windows/

Convert for Windows
Convert is a free and easy to use unit conversion program that will convert the most popular units of distance, temperature, volume, time, speed, mass, power, density, pressure, energy and many others, including the ability to create custom conversions!


I have the short cut on my desk top.  Of all the widgets I use it gets used just a shade more than George's round ball calculator and XE.com currency converter.

 

[jeeper1]

I've been using the same converter as mentioned by DD. I have an icon on my desktop for it as it gets used often.

[armorer77]

Here are the pics from todays shoot .

The victim



The Perp



3rd shot : 500 grs. 4F w/ 2 1lb. balls




4th shot 700 grs 4F w/ 2 1 lb balls




The final shot of the day 1000 grs. 4F w/ 4 1 lb. balls



The results

[Double D]

I just dug out my Muellers and he is what he says about proof-synopsized.

English method.

a charge of powder which weight as much as the shot in all pieces.

Brass 24 pounder 20 pounds, Iron 24 pounder is 18 pounds.

France used 2/3 of the shot weight.

Mueller says the better way to proof it is load it with a standard load and fire it 2-300 times a quickly as possible and see if it survives.

Mueller also reports on a another French method. Instead of shot, ram in as hard as possible 2 feet of clay.  Mueller says he doubts an irion cannon could stand  such a proof.

So using the English method, and George's round ball calculator, you have a .19 pounder, so load a .19 pound iron ball over .19 lbs of powder for a proof load.

[armorer77]

Here is a standard shot 300 grs 1F

 


Somebody let me know if this link works please . Armorer

[intoodeep]

No worky... So, I teaked it for ya! 

[armorer77]

Thank you . That was a standard load . 300 grs. 1F w/1 lb. lead ball . Armorer

[Double D]

Use the embeded code line not the url.

[GGaskill]

For another historical note, when the Ordnance Dept was testing the Griffen gun (the predecessor of the Ordnance rifle), after firing something like 500 shots and encountering no wear, they decided to blow up the gun (in the interests of science, I'm sure.)  It took 7 charges and 13 shot (they filled the bore) to burst it.  I don't think you will be able to burst yours.

[RocklockI]

but after being torched to within an inch of it's life , and in the interest of science .

and spirit of the mythbusters .....if your going to test it "to destruction" , well destruction should be goal ....  'by whatever means nessesary' .....which means ..........a charge of bp and something else if you could think of something else to add .....

clay sounded like a good idea to plug the barrel . insert a 'mesurering stick' to leave a looseage powder chamber , even with severe overload .

if possible use an electrical igniter ........? with wires that go thru the clay and into the loosage powder chamber ,containing a severe overload  .

with a 'booster' within a booster to spank that parrot into orbit .

maybe put a plug in the muzzle sealed with jb weld .

i have no idea how any of this could happen and do not recomend this to anyone ...whoso ever !


i've never thought about trying to blow one up ......? silly me   .   so any info ,all info , and /or any precieved info that anyone thought was info ....was wrong . i recomend agianst it  .

even thinking about it might be a crime .......in some states ......maybe more .

black powder muzzle loading cannons .

[Victor3]

 Armorer77,

 Thanks much for conducting the test. I hava a few questions...

 You say up above that the cannon has a 1" chamber. I'm wondering how much powder it holds. I assume that on your heavier loads, some of it must have been overflowing into the larger diameter bore?

 On your final shot, about how far did the 4 balls go?

 In measuring the OD for change, were you using the vernier calipers shown below