Weird Pressure Question

Model12Win · April 11, 2016, 11:54 PM

Hello all! Now this is a weird one, even for me to ask!

I am trying to commission someone to build me a replica of a 14th century bronze handgonne (hand cannon). If you click "Medieval European Handgonne #1" HERE you will see the .55 caliber original bronze specimen I am trying to have recreated for me. I am going to have it made in .540" caliber so I can use .54 cal balls and patches that I already have plenty of. This specimen seems to have a thick barrel, as most handgonnes do, and tapers to the end. The breech should be something like an inch and a half wide, and the muzzle looks to be about an inch wide with .55 bore.

So, assume we are using a traditional bronze of 88% copper and 12% tin, and I was using 230 grain .535" lead round balls with a thin patch, and maybe up to 40 grains of FFG black powder, and a simple bronze barrel of the dimensions shown in these pictures, how safe do you think that would be? What kind of pressures would said load produce?

I have seen people make reproduction handgonnes in brass and fire them, so I am curious. Of course I could always just have one made from steel, but I would love to have an authentic one made of bronze.

So what do you guys think? Will this be safe provided I don't overload it? Thanks!

Branko · April 12, 2016, 03:35 AM

Pretty sure it'd be okay.

With 40 grains of FFG you'd be most likely looking at pressures somewhere below 8000 psi, if confined, which it won't be since it's thicker on the inside then on the outside and loaded from the front the gas can just escape to the sides of the ball.

Captchee · April 12, 2016, 06:33 AM

I think pressure wise you would be safe if it was properly made . Bronze however work hardens .eventually turning into a grenade at the end of a pole .
Probably one of the reasons your having an issue finding someone to make you one .
If you did I would be willing to bet it would be un drilled for the touch hole .
A safer option would be to go with a yellow steel alloy .
Might see Ed Rayl about his muzzle loading barrels
Past that , if you must have bronze . I would line the bronze barrel

g.willikers · April 12, 2016, 09:47 AM

Brass or Bronze?
http://www.diffen.com/difference/Brass_vs_Bronze
Maybe to help be safe when shooting, it could be inserted inside something stronger, like maybe high pressure pipe.
Then remove it for display.
Just a thought devoid of actual knowledge on the subject.

Jim Watson · April 12, 2016, 10:27 AM

Bronze was once known as "gunmetal" because it could be cast better than iron. In the muzzleloading cannon era, iron guns were considered cheap and nasty when not outright dangerous.

Wiki says standardized admiralty gunmetal is 88% copper, 10% tin, 2% zinc.
Doubt the handgonne makers were so careful. But they didn't have liability lawyers, either.

foolzrushn · April 12, 2016, 10:40 AM

I think there may have been a reason that a 'handgonne' was not in the hand, but on a (longer is better) stick. And one could take something from the spelling and meaning thereof.

That said, considering your location, you might want to consult with
www.kansascannonworks.com if you don't already know of them. They may have some suggestions or such. Weight at that length may affect your choice of materials too.

There is a thread on ar15.com about mini cannons with links that may be relevant..or not. It seems to me that basically a mini cannon 'on a stick' (nod to Jeff Dunham) is what they were.
https://www.ar15.com/archive/topic.h...&f=5&t=1511655

I have seen minis at shows...they look like fun, but are expensive.

Be Careful!!!

Branko · April 12, 2016, 01:11 PM

Yes, bronze was used extensively for cannon, until cheaper iron cannons became a thing.

Model12Win · April 12, 2016, 05:37 PM

^ So "yes" as in it should work?

Boogershooter · April 12, 2016, 08:54 PM

Fort Bend iron works in Fort Bend Indiana is who builds most repros. I havnt delt with them in several years but they will be your best bet.

Boogershooter · April 12, 2016, 09:10 PM

South Bend is the correct name. Sorry for the confusion.

Model12Win · April 12, 2016, 10:14 PM

Thanks Booger, I'll have to look them up.

I just need to make sure it will be reasonably safe to have one made.

Thompsongunner · April 13, 2016, 12:09 PM

Why not just get one from the company you hyper linked to?

Model12Win · April 13, 2016, 05:43 PM

They are defunct and don't make them anymore, otherwise I would.

Thompsongunner · April 13, 2016, 06:53 PM

Well then do you have any machinist friends that do any shooting?

Model12Win · April 13, 2016, 07:02 PM

Lots of shooter friends, not so many that do "the machining" as it were.

Branko · April 14, 2016, 04:00 AM

I have a neighbour who works in whatever metal which can be machined, but other side of the world.

There's got to be small time machine shops which can do it for you if you provide the blueprints, though.

April 12, 2016, 09:47 AM	#4
g.willikers Senior Member Join Date: September 28, 2008 Posts: 10,442	Brass or Bronze? http://www.diffen.com/difference/Brass_vs_Bronze Maybe to help be safe when shooting, it could be inserted inside something stronger, like maybe high pressure pipe. Then remove it for display. Just a thought devoid of actual knowledge on the subject. __________________ Walt Kelly, alias Pogo, sez: “Don't take life so serious, son, it ain't nohow permanent.”

April 12, 2016, 10:40 AM	#6
foolzrushn Senior Member Join Date: April 29, 2015 Location: middle of the Santa Fe Trail Posts: 396	I think there may have been a reason that a 'handgonne' was not in the hand, but on a (longer is better) stick. And one could take something from the spelling and meaning thereof. That said, considering your location, you might want to consult with www.kansascannonworks.com if you don't already know of them. They may have some suggestions or such. Weight at that length may affect your choice of materials too. There is a thread on ar15.com about mini cannons with links that may be relevant..or not. It seems to me that basically a mini cannon 'on a stick' (nod to Jeff Dunham) is what they were. https://www.ar15.com/archive/topic.h...&f=5&t=1511655 I have seen minis at shows...they look like fun, but are expensive. Be Careful!!! __________________ If you feel that you're pretty important...you should think about your significance to the Universe....and re-evaluate ! certified 'soap welder'

April 11, 2016, 11:54 PM	#1
Model12Win Junior member Join Date: October 20, 2012 Posts: 5,854	Weird Pressure Question Hello all! Now this is a weird one, even for me to ask! I am trying to commission someone to build me a replica of a 14th century bronze handgonne (hand cannon). If you click "Medieval European Handgonne #1" HERE you will see the .55 caliber original bronze specimen I am trying to have recreated for me. I am going to have it made in .540" caliber so I can use .54 cal balls and patches that I already have plenty of. This specimen seems to have a thick barrel, as most handgonnes do, and tapers to the end. The breech should be something like an inch and a half wide, and the muzzle looks to be about an inch wide with .55 bore. So, assume we are using a traditional bronze of 88% copper and 12% tin, and I was using 230 grain .535" lead round balls with a thin patch, and maybe up to 40 grains of FFG black powder, and a simple bronze barrel of the dimensions shown in these pictures, how safe do you think that would be? What kind of pressures would said load produce? I have seen people make reproduction handgonnes in brass and fire them, so I am curious. Of course I could always just have one made from steel, but I would love to have an authentic one made of bronze. So what do you guys think? Will this be safe provided I don't overload it? Thanks!

April 12, 2016, 03:35 AM	#2
Branko Senior Member Join Date: October 9, 2015 Location: Croatia Posts: 188	Pretty sure it'd be okay. With 40 grains of FFG you'd be most likely looking at pressures somewhere below 8000 psi, if confined, which it won't be since it's thicker on the inside then on the outside and loaded from the front the gas can just escape to the sides of the ball.

April 12, 2016, 06:33 AM	#3
Captchee Senior Member Join Date: April 2, 2013 Posts: 439	I think pressure wise you would be safe if it was properly made . Bronze however work hardens .eventually turning into a grenade at the end of a pole . Probably one of the reasons your having an issue finding someone to make you one . If you did I would be willing to bet it would be un drilled for the touch hole . A safer option would be to go with a yellow steel alloy . Might see Ed Rayl about his muzzle loading barrels Past that , if you must have bronze . I would line the bronze barrel

April 12, 2016, 10:27 AM	#5
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,543	Bronze was once known as "gunmetal" because it could be cast better than iron. In the muzzleloading cannon era, iron guns were considered cheap and nasty when not outright dangerous. Wiki says standardized admiralty gunmetal is 88% copper, 10% tin, 2% zinc. Doubt the handgonne makers were so careful. But they didn't have liability lawyers, either.

April 12, 2016, 01:11 PM	#7
Branko Senior Member Join Date: October 9, 2015 Location: Croatia Posts: 188	Yes, bronze was used extensively for cannon, until cheaper iron cannons became a thing.

April 12, 2016, 05:37 PM	#8
Model12Win Junior member Join Date: October 20, 2012 Posts: 5,854	^ So "yes" as in it should work?

April 12, 2016, 08:54 PM	#9
Boogershooter Senior Member Join Date: December 9, 2014 Posts: 645	Fort Bend iron works in Fort Bend Indiana is who builds most repros. I havnt delt with them in several years but they will be your best bet.

April 12, 2016, 09:10 PM	#10
Boogershooter Senior Member Join Date: December 9, 2014 Posts: 645	South Bend is the correct name. Sorry for the confusion.

April 12, 2016, 10:14 PM	#11
Model12Win Junior member Join Date: October 20, 2012 Posts: 5,854	Thanks Booger, I'll have to look them up. I just need to make sure it will be reasonably safe to have one made.

April 13, 2016, 12:09 PM	#12
Thompsongunner Junior Member Join Date: January 3, 2013 Posts: 13	Why not just get one from the company you hyper linked to?

April 13, 2016, 05:43 PM	#13
Model12Win Junior member Join Date: October 20, 2012 Posts: 5,854	They are defunct and don't make them anymore, otherwise I would.

April 13, 2016, 06:53 PM	#14
Thompsongunner Junior Member Join Date: January 3, 2013 Posts: 13	Well then do you have any machinist friends that do any shooting?

April 13, 2016, 07:02 PM	#15
Model12Win Junior member Join Date: October 20, 2012 Posts: 5,854	Lots of shooter friends, not so many that do "the machining" as it were.

April 14, 2016, 04:00 AM	#16
Branko Senior Member Join Date: October 9, 2015 Location: Croatia Posts: 188	I have a neighbour who works in whatever metal which can be machined, but other side of the world. There's got to be small time machine shops which can do it for you if you provide the blueprints, though.