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Want to Build mountain howitzer

7K views 32 replies 6 participants last post by  double d 
#1 ·
Hello,
I would like to build a golf ball bore mountain howitzer. I would like to make it period correct out of bronze. Does anyone know of anyone making such a thing?
 
#5 ·
#7 ·
Thanks everyone. I already contacted them.

On a side note, what is your opinion of Coaches Club Cannons? I noticed they are not on the list on this forum. And what are your opinions of Hern cannons?

I wish I had found this forum sooner. I purchased a golf ball naval cannon on eBay. The maker is a Man named Chuck from Minnesota. It’s 1018 steel. The powder chamber is 1 inch by 8.75 inches and the total bore is 16.25 inches. The breech is 2 and 5/8 inches thick. My largest charge was 400 grains 1F goex. Made a great boom but I think I will stay around 250 grains to 300 grains.
 
#11 · (Edited)
Jack Hern is one of us. Hern cannons has been around for a long time. I think bu I am not usre, that Jack is second generation in the business, maybe thrid. They supply people like Dixie Gun works. Our own Zulu has provided Jack a mold for the there new Verbruggen gun. TM333TX, Trey has one the barrels and built a carriage for it. Look at this post. https://www.go2gbo.com/forums/88-bl...before-1849-first-model-prairie-carriage.html

Coaches Club is not on the list. Two reasons. First I am not real good about keeping the list up to date. That is on me. Second is their designs. I inquired about their guns when they first came out several years back. The responses were not very confidence building. They lacked the knowledge of safety standards in cannon building. They do some very nice machining. Look at their billiard ball cannon, beautiful gun, but it uses a powder chamber. Barrel is made of 1018 steel.

Edwin Sarkissian of Youtube fame has a Coaches club bowling mortar. He was been shooting it with smokeless powder. but has changed to Triple 7 lately. Edwin has folded the carriage in half. The barrel is made from a pressure bottle. It shows signs of bulging and the welds for the welded on chamber have started to break. He still shoots it. While I am not all that thrilled by Coaches clubs guns, I have to give them credit, the carriage folded but the barrel hasn't failed-yet, despite the abuse.
 
#9 ·
BrendanB,

Check with South Bend replicas. They used to make a 1/2 scale Mt. Howitzer tube. I believe it was 1.5" and not GB size.

I have always wanted one too. Just has not come to pass. Below is a bit of eye candy. I came across these photos years ago and saved them for reference. I do not know the owner I believe he was from AZ. At one time I was going to try to track it down to see if it was for sale.
 

Attachments

#12 ·
Thank you for the info, and that thread is amazing. What a build!

Double D, I am new to this. So please forgive my green question. But... my golf ball cannon that I purchased on eBay... it’s 1018 steel with a 8.75 inch x 1 inch powder chamber, and a 7.5 inch golf ball size bore. The total bore is 16.25 inches. It sounds like what I bought is essentially dangerous, if I am understanding your comment correctly. Ugh.... I really wish I had found this forum sooner.
 
#17 ·
What ever you have it is probably OK-1018 steel s fine for blackpowder. But why an 8.75 inch long reduced chamber? Any time I see the reference to some one offering reduced chambersin all their designs I see someone who really doesn't quite understand cannon design, and especially one so long. They are building in a safety problem. Max safe recommended load for 1 inch is 180 gr cannon of Fg powder. Loaded in a 1 inch cartridge, that cartridge is just about 2 inches long.



How do you fill the remaining 6.75 inches of that chamber, your 1.68" golf ball won't fit. For that matter how do you get a cartridge into that chamber to start with. How do you align a foil cartridge with a 1 inch hole at the bottom a 1.72 inch hole. Tip the gun up? That how its down with little table top guns. but it's awkward and unsafe You can't leave that airspace, particularly in front of a cylinder, that sets up the Vielle effect. (discovered with the advent of smokeless powder, but perfectly applicable to blackpowder also)

This is the danger part. If the gun builder doesn't understand how to build a proper chamber or the problems he is creating by building such a chamber what else doesn't he know?

I assume you mean .75 golf ball bore, not 7.5.

The recommendation is that a barrel have walls over the chamber the same thickness or greater than the diameter of the powder chamber. A one inch chamber then must have one inch walls and be at least three inches in diameter over the chamber.

To many builders try cut corners and make a reduced chamber so they can use a smaller piece of material to build larger bore gun.

I found the numbers on line for the diameter of the base ring of the Mt. Howitzer- 7.6 inches. Using Georges, scale number of .379 means you need a piece of material 2.88 inches in diameter. The original powder chamber diameter was 3.94 in diameter. (number from trying to read this drawing from https://www.go2gbo.com/forums/88-bl...tzer-me-design-project-assistance-needed.html. Click on the attachments link in the post to see pictures.) That would scale using George's number to a 1.49 inch diameter chamber. Scaling down the 6.3"diameter of the original barrel over the chamber, gives 2.388 diameter for golf ball. Divide this by three for recommend safe wall thickness, (wall thickeness equals chamber diameter) gives a safe chamber diameter of .796.

These are the type of numbers you need to check when buying or building a cannon. Anytime a cannon maker says reduced chamber make that a yellow light-caution. Check them, do the math. Reduced chambers can be safe-if done right. But are not really necessary for most guns.

 
#14 ·
I am not sure if this is how it is done but I took the numbers from Hern's howitzer
Their barrel is 37.5" and 2.25" bore

1.75(GB SIZE) ÷ 2.25 = .777777778

37.5 × .777778 = 29 and some change roughly 30"

That's how I came up with 30" idk if that is how it works
 
#15 ·
The Hern is underbored at 2.25"; the original was a 12 pounder which is 4.62" bore diameter. Sooo:


1.75(GB SIZE) ÷ 4.62 = .379


37.5 × .379 = 14 1/4 or so


I suggest you make the tube to one half scale but underbore to golf ball diameter for a satisfactory piece, especially if you do it in bronze. There is a thread here I did about making a one half scale bronze mountain howitzer. See Half Scale Mountain Howitzer.
 
#25 · (Edited)
It does make sense, and it illustrates perfectly what I am try to tell you. That one inch diameter powder chamber only needs to be about 2 inches deep, not 8.75 inch deep.


A chamber that deep just begs to be improperly loaded. It is so simple to not seat the charge all the way to the bottom or leave a cylindrical air space between cartridge and projectile. Then of course some one is always going to try fill that chamber. The maximum recommended safe load for one inch bore is 180 grain which makes up into a cartridge about 2 inches long.

When I see a chamber like that, it tells me the maker has no idea how to make a safe cannon. They should be avoided.

When loaded the projectile should sit on and be in contact with the powder-no airspace.

Wall thickness is fine, length of chamber is not.
 
#20 ·
I made this set of implements for a Brooks golf ball bore 24 pounder.
Note the "V" shaped piece on the right. It slides in the bore and makes a perfect pathway to push a powder charge straight into the powder chamber.
The double ended worm is bore size and chamber size.
Same with the sponges.
Zulu
















 
#21 ·
The guy I bought it from said my max charge should be 500 grains. I have only gone up to 400 so far did that on the 4th of July. And have stayed at 300 most of the time. It has only been a noise maker for me so far. I have not shot a golf ball yet. My schedule has not permitted me to take that drive out to the desert yet.
 
#28 ·
Thank you Double D for your advice. You guys are the first people I have ever met that have vast knowledge and experience on cannons, I really appreciate that. I have 2 young boys with special needs and now I know not to fire that cannon anymore.

Could you recommend someone with knowledge and wisdom that I could possibly send it to and have looked at and potentially fixed? I want to be as safe as possible and I do not believe sending it back to the original maker is a wise idea at this point, considering what I have learned from you. And I really do appreciate the information. I believe you may have saved my life or someone else’s with this information. Thank you very much!
 
#31 · (Edited)
Without diameters, the drawing in post #18 doesn't have enough information to make any recommendations beyond return to the seller with a statement that you do not consider the design safe. If you don't want to do that, I guess you will have to eat the cost.


If the diameter(s) is(are) large enough, it could be modified to be safe.


The muzzle ring diameter of the 12 pdr bronze howitzer is 6.9" at full scale.
 
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