Herniated disc cannon

[thelionspaw]

O.K.. Here goes "Plan B". Until I mend, I'll have to be satisfied with this one. You can tell buy the dust that it came from a back burner.

I do not know how to handle these little guys. The bore is 16mm (5/8") and I would imagine I'd have to touch it off with a heated pin since the vent is tiny? I only have ffffg and fg.. Not too keen about experimenting on my own. El Cazador!  Where are you?

Richard "The Chicken"

n.b. the powder cans are out in the garage so I used a .357 mag cartridge

[thelionspaw]

Here are (I hope) more images. I still do NOT know how to handle this computer.

[EL Caz 66]

Hey Richard,

Now that's cool looking thingy you have there, now with something like this would I would start my loads in tiny increments, Trial and error my friend. I do have plenty of those fuses you need, I'll send you a hand full.

ED

[Double D]

Now Richard, the cannon is neat, post it up in the calendar post, but tell me about the BSA Model 12----of course after you tell us about the cannon. We don't want the moderator nagging us about topic drift!

[dan610324]

ooooooohhhh    thats an really nice early bombard , I would guess 1450 - 1500 style .
if I was you I should be very careful with the loads , it wouldnt be fun to ruin that little beauty .
and from the photos it doesnt look all brand new either .
please let us have some more info , all diameters and depths ( inside and outside ) .
the upper beam that hold the barrels elevation ,
is it an repair or is it an reinforcement of the beam in the middle ?? ok doesnt matter what , it add lots of charm to the cannon .
if you want an full chamber you can fill it up with oat meal or baby powder after you put in your bp load .
I would probably use the ffffg in extremely small amounts if I should test it , but thats if I only had ffffg and fg to choose from .

[Cannoneer]

Richard,

   Your bombard model is a beauty, and I know miniature artillery makers often vent their barrels for realistic effect, but in my entirely unsolicited opinion I don't think this model was made with the intention to actually fire it.

[dan610324]

I must agree totally with you boom j
that's why I asked for all measurements .
but if it has an historic original it might be so close in dimensions that it could be safe to fire with SMALL charges . but they must be very small

when I'm looking at the top photo and know the bore is only 16 mm I would guess that the chamber is just 4,5 mm or so in diameter . but the wall thickness of the bore isn't more then approximately 3,5 mm .
that's very little , but could be accepted in an reduced chamber gun if the charges are extremely small .

whats concerning me even more is the chamber walls , they are probably not more then 2 mm thick .
that mean only half the recommended wall thickness .

by the position of the vent I would guess that the chamber is approximately 10 mm deep , that means it can take an considerable amount of powder compared to its outer dimensions .

my recommendation is to fill the chamber with powder and then use an high quality scale to weight the charge ,
when you got the weight of the powder in the chamber I would take one fifth ( 1/5 ) of that weight for my first blank charge .

I would never try to shoot an full weight ball in that gun  ( lead or iron ) .

remember that those guns where used to shoot stone balls ,
they have an weight of approximately only 1/3 or 1/4 of an iron ball .

if I should shoot an projectile from that gun ( but I would never do it ) , then I would try to find an very light ball to use . why not try to cast an ball in gypsum ( plaster of Paris ) and wrap it in a few layers of aluminum foil ??

but remember that an lead ball is 5 to 6 times heavier then an stone ball , that mean it will accelerate much slower in the bore .
this led to an much smaller volume for the gasses from the powder and an extremely rise of pressure , the pressure will peak to heights those walls cant take .

IF YOU ARE GOING TO SHOOT IT BE EXTREMELY CAREFUL .

[thelionspaw]

At this point, I have no idea if an image will appear but DD has patiently been tutoring me. I want to do this new image for the calendar. As for text:

Dan; The beam hasn't been repaired. That is an assumed stress point in original period construction and it has been reproduced in this miniature as an original point of construction.

DD; You have good eyes. Yes it is a 12 but it was a rare Sherwood Rook that I had converted to .357  with Griffen & Howe doing the chamber and bluing but Douglas doing the rifling and Fagean restoring the wood. Slinged and prone with 3 shot groups, it links all 3 with .38 special at 100 yards. Never went beyond that with paper; so who knows?

It's Italian Walnut.

[Double D]

Myth Busted! From one old dog to another, we can teach old dogs new tricks.  The picture looks great.  A lot you can do with right click.  Move your cursor all over the board and right click on things  and see what it says...powerful tool that right click.

I do like this little gun, should make a good calendar subject.

I'll send you an adress where you can send that 12 for extensive field testing....I have a couple thousand rounds of 38 special and lots of gophers.

[Cannoneer]

Richard.

   I think your model may be made from a kit. I never had this Mantua Model Co. - Leonardo da Vinci bombard kit but I did put together a couple of their other models. If it is from this model company it definitely was never meant to be fired; even with a minute amount of powder.

https://www.mantuamodel.co.uk/prod.asp?product_idx=159&imgstate=1

[Double D]

Hey Boom,

Why don't you open a new topic on the model cannon link you posted above and tell us all about the cannons they sell.  What they are made of, how hard the are to make etc.

We have some folks here who may not have the equipment to build cannons from scratch but can build form a kit.

I know ai have some questions for you.

[Cannoneer]

Why don't you open a new topic on the model cannon link you posted above and tell us all about the cannons they sell.  What they are made of, how hard the are to make etc.

I'll post some info on this topic even though I'm not to sure that many other members are going to be all that interested in non-firing manufactured miniature artillery kits.

[dan610324]

I believe many would be interested , at least I would be .
also if they are to been looked at as non firing cannons they are very beautiful and interesting.
many people dont have time and space to build an larger model . but this small beauties you can build at your kitchen table with an minimum of tools .

[Nasty Jack]

I may be showing my age  here . . .

Hobby shops used to sell model jet engines which used pellet fuel. The brand name was Jet X. A search of Google suggests that they're out of business. But model shops sell rocket motors, and I'm sure they would sell fuse -- small diameter stuff, 1/16" . . . 0.0625" although I doubt it's spec'd to ten thousandths. 

I'd stay away from the fine grain FFFFg powder. That's for priming pans in flintlocks, or making quills for large cannons.

[shooter2]

I'll add my two cents worth here.  I would like to see some info about models and the construction thereof.  So, please BoomJ enlighten us. 

Shooter2