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Discussion in 'Cannon' started by Col. Batguano, Jan 28, 2013.
Why again do we use no patches in cannons, resulting in windage around the ball?
So the tube doesn't blow up in our face?
Yes pressure reduction upon firing is one benefit.
The other is to make loading easier.
Recall the increased resistance to load a patched ball in even a smoothbore over the resistance of loading an unpatched ball in say a .50 cal musket for instance. The resistance is from friction of the circumference of the ball against the wall of the barrel.
A .50 cal ball has a circumference of roughly 1.6 inches. So you have 1.6 inches of surface area in friction contact with the barrel wall to over come.
It is recommended the over 1 inch cannons not be patched. My little 1/6 scale 42PDR 1841 boat howitzer has a 1 inch bore. The circumference of the 1 inch ball is 3.14 inches. That is lot more surface area in contact with the bore and a great deal more friction to overcome.
I also have a golf ball bore 1/5 scale of an 8 inch siege howitzer. Bore 1.72 and 5.72 inch circumference-surface area to overcome friction.
Now add in the other factors that were present during war shooting when cannons were deployed. Round shot was iron-it rusted, it wasn't always perfectly round. Windage was needed to get this shot down the the bore. Under normal circumstances shot was gauged before use, but this wasn't always possible in the field and during the heat of battle. There of course was the other issue that we don't have, that of an improperly or poorly cleaned fouled barrel. When a company of troops with fixed bayonets is charging your position you might cut corner loading.
Of course in our case we have plenty of time to practice safe load procedures insuring we only use the correct and perfect projectiles in immaculately clean bore---Right? Right!
I can tell you from my own experience loading 1 inch round lead balls, that it is very easy to stick ball in a bore. Several year ago while loading I slightly missed the bore and banged a ball against the muzzle, oops. Repositioned the ball and loaded the ball properly only to have it stick halfway down the bore. What a nightmare. That little tiny ding was enough to jam that ball.
I have gone so far now as to not even use lead balls in my cannons. I use nothing but zinc.
You and I have the same gun! 1" bored 1/6 scale 1841 42 PDR, mine on a naval carriage I built from plans. I shoot steel ball bearings in mine. I bought the tube from Ed at HMR cannons, as well as his beer can bored Coehorn mortar.
I usually shoot 250-300 gr. Fg behind the ball, and use a fuse for ignition. I have to think a turned steel tube with 1 1/4x bore breech thickness is safely built with those sorts of loads.
I'll show you mine if you show me yours...
I built this one in 1984 in Gunsmithing school. It is modeled after this gun from the U.S.S. Cairo
First gun on the right.
Unfortunately, mine is up north at my cabin, and I won't have access to it until the snow melts.
This looks substantially like one that had pictures posted on a mock gun deck on the GBO forum a couple of years ago.
With mine, I ripped and re-glued some quarter-sawn white oak to make the cheeks. I didn't have the heart to paint them, so I fumed them dark with the old ammonia treatment. Also built some scaled blocks for gun tackle. Like you, I left off the training loors at the rear of the carriage, and built a scaled gun deck for it, and put steel tires on the wheels, secured with gorilla glue.
Who made your tube?
I made the tube as a machine shop project in college....tapers, radii and deep hole drill. 4140 Anealed.
Do you mean this photo?
all the same gun
I'm guessin' that isn't just a signal cannon.
Rope rings were common to wad the cannon ball, depending on the aplication if the ring wad went infront of the ball or behind it.
I have never heard of rope rings before. Do you have some where I can learn more about them?
British Navy history the ring in front of the ball stopped the ball rolling down the barrel when the ship pitched about ,used on land as well by sailors maning guns with depressed elevation . Sailers made the ring wads with rope stock on board ship .
Also touted as the origin of the game of quoits, sailors throwing rings onto hooks for amusement .
Yup. Those are the ones!
What did you do for gun tackle blocks? I made mine out of white oak and dowels cut for the shiv wheels, and then seized them with a back splice of 3/16" rope. They're more decorative than functional though.
Went down to the Hardware store and bought some brass double blocks and strung them with real hemp. My blocks are very muck functional. They work in concert with the breeching to dampen recoil
Have shot some blanks usually when every one else shooting firecrackers.
I was looking for something factory made, but couldn't find anything. that's why I made them. Though I think wooden blocks were more prototypical, they were quite a chore to make. I couldn't find real hemp rope either, so I wound up with 3/16" sisal. Too thick, but it's the smallest I could find that still actually looked like real rope.
What's a typical charge shooting a projectile for you?
Mine is usually 300 gr. Fg or FFg behind a 1.000" steel ball bearing. My bore dimension is 1.06", so it just rolls in. I cartrigize my powder bags in tin foil and pre-mark them as to grain and charge size.
Ouch what a massive over load. The maximum recommend load for a 1 inch bore is 185 grins of Fg. Okay so I use 200 grains of Fg.
Here is 200 gr. Fg and a 9 oz. Slug.
Here is 200 grain FG and a 3.4 oz round ball.
You can see why I don't use the 9 oz slug any more...tears up equipment.
Marine Hemp Rope
Click on the pictures to see the video's.
I'm not sure it's that much of an overload. Shooting steel it's a lot lighter than a lead round ball, and with that much windage, and 1.25" of steel around the breech, I think it's ok.
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