Here are a couple pictures of a cannon I built in 1977-1978. The barrel is cold rolled steel, about 3-1/2' long, 1" thick wall, 3.25" inside, 5.25" outside. The barrel was selected based on what was available, and what had a good fit to one of the standard tin can sizes. 3-1/4" happens to be a perfect fit for most vegetable cans! The breech plug was a 5" long piece of 3.25" shafting. We left it out an inch and then filled that 1" groove with weld and then smoothed it with a grinder. Barrel lugs are pieces of 2" shafting welded on. Large timbers were used for the carriage 8X8" for the cross beam and 10X12" for the main beam. 2" thick planks were cut and trimmed for the cheek pieces, but for added strength, 1/4" plate was mounted in back of the cheek pieces such that the barrel lugs passed through that steel and then on top of the wooded pieces. Several 1" bolts passed through the entire thickness of the cheek pieces, the steel plates, and the center beam to hold the entire assembly together. The lower ones also went through the 2"X2" angle iron to attach the cross beam and axle. A valve wheel acted as the elevator on the back of the barrel. The wheels were obtained from a local farmer from an old circa late 1800s/early 1900s wagon. The wagon was out in the field falling apart, and only two of the wheels were usable. He agreed to give them to me, and even brought out his torch to cut them off. They were 48" tall, with 2" wide metal bands around the rim. Spokes were wooden as was the outer and inner rims. The central hub was steel with a 2" square steel axle. I ran the square stock all the way across under the cross beam and then used bar stock and 1" bolts to clamp the axle to the square stock.
When done, the whole cannon is 4' tall and about 7' or so long. Many different types of ammo was used ranging from cans of concrete, empty cans filled with sand and nested, cans of vegetables, and pieces of firewood! We had many many years of fun with it up on Little Sebago Lake in Maine. Once I moved away, it was stored at my brother's house and I rarely got a chance to fire it. I finally put it up for sale about 7-8 years ago and sold it for $1000. Don't know if that was a good price or not, but it was certainly a lot more than I paid for it! If I don't count my time, I think it might have cost me $40-50 for all the parts and pieces.
unfinished cannon:
finished cannon (check out those 1978 sideburns!!):
This last picture is a night time firing picture of my first cannon project. It has a 1" bore. Like the bigger one, all parts were purchased as scrap, salvaged from the junk piles at the paper mill I worked at in the 70s. The barrel was heavy wall steel, 1" ID, 2.5" OD, 20" long. The breech plug was a 1.25" bolt, tapped and threaded into the back end. The carriage was pieces of pipe and plate, bent and welded into the appropriate shape. A large threaded rod from a big gate valve acted as the elevator on the back of the barrel. The wheels were 14" diameter solid cast iron wheels from an old 4 wheel cart.
