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Discussion Starter #1
Saw this yesterday, don't know much beyond what you see in the pix. The barrel he started with was a USAF GAU-8A 30mm Gatling gun barrel that's had the front end cut off so it is about half length. The original cartridge chamber is still in it. The barrel locking lugs were turned off, and threads put on to take a screw-on breech cap you can see resting on the trail of the gun.

The seller of these barrels supplies smokeless powder and encourages customers to use it in the cannon, but I strongly disapprove of that practice since all kinds of bad things could, and probably will happen. That's really an understatement, using smokeless powder in bags or loose, in something like this is pretty much suicidal. Use black powder of proper granulation only, when you have what is now an "antique system" like this.

I think the shooter who owns this actually IS using black powder despite what the seller of the barrel may have told him he could get away with.

Click on thumbnail below to enlarge the picture.








 

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Forgot to mention, this "antique system" in its basic mechanical setup, resembles Whitworth's rifled breechloading cannons, that also had screw-on breech caps. Whitworth used tin cartridge cases.
 

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A very nice cannon.

Since this tube was as far as I know intended to be used with smokeless powder perhaps a correctly weighted amount of it (as much as was used in these cannons) could be used?
 

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The rule, long established, is that smokeless powder (not including Pyrodex etc.) is not to be used unless is in a properly designed cartridge with adequate priming and separate ignition charge if required. Just one of the problems you can run into with charge geometry is standing wave generation. Standing waves really have no limit as far as psi, and most instrumentation ends at 200,000 psi or so. I've known standing waves to blow up a Navy 76mm gun just because a flash suppressant charge was put in and changed the internal geometry of the charge very slightly.

Don't do it unless you have an advanced degree in engineering, have worked it all out, and have experience in that field, or you will probably blow the gun. Anyone with those qualifications won't do it anyway, they know what'll probably happen.

I also saw a 16" naval gun blown up because some engineers decided to shoot a blank charge with a hay wad. They used 40mm Bofors gun powder as the noisemaking charge. That hadn't been done before but it oughta work, right? Wrong! The 40mm powder didn't like that geometry and decided to detonate, which welded the breechblock into the threads, and it never could be opened again. The gun had just been refitted and drilled for pressure ports for testing, at a cost of about $5M of your money.

If you are bent on suicide, go stand in front of a train, it is less painful than having high-velocity metal fragments rip into your body.
 
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