Help needed for first full scale cannon

[cdn_army]

hello everyone

Ive been reading alot looking to get as much information as I can....good thing that I'm only 31 because there is alot of information here!

Now I've started on the path of black powder cannon with a 1/2 scale 24 pounds Coehorn mortar. I'm still loving it! but I'm starting to get the call for something bigger.... Since I'm limited in space i am looking at a full scale mountain howitzer. So I did some research online, and it seem that the more I read the more questions are poping into my head. sleeve or no sleeve..seamless or DOM  iron or bronze...obviously money is also a factor.

I know the original mountain howitzer had a sub chamber, but based on my understanding of what i read online, if the fit between the breech plug and the main tube is not tight enough, water and combustion byproduct could sneak in between, and therefore leading to corrosion issues down the road. Am I right or totally wrong?

Could it be possible to have the howitzer made without a sub chamber?

now for the caliber..I'm not going to participate in any official competition and would prefer use ammo that are easily available, like pop can, or can of soup etc. any recommendation ?

Any other advice that you may think of, please feel free!

Here in Canada cannon shooting is pretty much non existant, so resources are far and between

Here is a link of my mortar in action, in case you guys would like to see. I made the carriage myself...I am not woodworker, but it serve the purpose
http://www.youtube.com/watch?v=ubpv7ItdIQU

Thank you

[GGaskill]

Regarding scale and bore size, figure out what you are going to use as projectiles first.  There does not seem to be a standard can size that is a good fit for the 12 pounder bore (4.5" shot, 4.63" bore.)  Two liter soda bottles are about 4 3/16" so you could under bore for them but be reasonably close.

The mountain howitzer has a smaller chamber and I wouldn't make it with a full length 4.62" bore because the area over the chamber is reduced in diameter (6.300".)  If you want a cylindrical bore, bore it undersize so the chamber walls are adequately thick or use a different gun as a pattern.

[RocklockI]

Welcome ,cdn_army !
I only have one question , Do you have a crew ?
 
Gary

[cdn_army]

I don't have a proper crew, I have a few friends interested in the project but nothing official yet

[dynomike1x1]

I shoot pool balls from my Mt. Howitzer and it's plenty loud for me. look at my vidoes and you can tell.

[cdn_army]

Ok after some more reading and advice from knowledgeable people, I would like your opinion on my take of a full scale mountain howitzer with a soda can size bore.
Please keep in mind that I don't have a CAD program so I had to use good old paint, therefore some measurement might be missing. I would really appreciate if you guys could share your opinion, like and dislike.

[GGaskill]

The front of the chamber should be tapered to eliminate a corner where debris could accumulate.  As long as it ends in the bore size part of the barrel, I think you will be OK.

[Cat Whisperer]

The front of the chamber should be tapered to eliminate a corner where debris could accumulate.  As long as it ends in the bore size part of the barrel, I think you will be OK.

I hadn't thougth of that, that would ease loading the charge as well!

GOOD job on the drawing!   I want one!

[Double D]

The front of the chamber should be tapered to eliminate a corner where debris could accumulate.  As long as it ends in the bore size part of the barrel, I think you will be OK.

Check the notes on the drawing. That's a pretty good paint drawing.

[cdn_army]

Thank you all for your help and advice!

now I just need to find a machine shop!  Using paint was not as bad as i tought, but I must say that having the original drawing, and only redoing the bore part made everything much easier!