Federov-Fox, If you do just these four things you will get more of a response from people who can make many different styles of cannon.
First, Decide the style you want. Example: 1857 Napoleon Gun-Howitzer, used extensively by both sides during the Civil War.
Second, Decide what scale you want. It seems you know that already, because a beer can howitzer needs to be drilled or bored to 2.665" if you go by the 1/40th rule. 2.60"(beer can O.D.) / 40 = .065"( amount of windage) + 2.60" = 2.665"(bore size). To get the scale from the bore sizes, you divide the beer can bore size by the original Napoleon bore size: 2.665" dia. / 4.62" dia. = .577 or the beer can bore is 57.7% of the original. Just about everyone would round that to 50% and call the resulting gun one-half scale. So, if you have someone build a "Stand-Off Scale" gun, they could take the over-all-length of 72" and divide that in half to get 36" total length with a bore length of one-half of the original which was 65", yielding a beer can bore 32.5" long. You could apply the same type of calculations to any one of a bunch of shorter length cannons too.
Take the 12-pdr. Howitzer for example. It was 53" long, so 1/2 would be 26.5" with a 20" bore. the weight was 788 Lbs. originally, so a one-half scale replica would be 98.5 Lbs. Take the divisor in the scale of 1/2 which is 2 and cube it 2x2x2=8 and divide the original weight of 788 Lbs. by 8 which yields a replica weight of 98.5 Lbs. So the gun and carriage would weigh only 180 to 220 pounds total. That size and weight is pretty easy to handle with a single friend to help.
Third, examine your ammo options and make sure you are up for creating concrete filled cans or what ever you decide on and make sure you accurately measure the can AFTER it has cured to make sure it has not swelled or that your calculated bore size will accommodate some out-of-roundness in your projectiles.
Fourth, Make sure your proposed cannon maker knows your upper price limit so he can guide you as to what size and type is possible for that amount.
Just a few suggestions and hints to use or not. That is strictly up to you. Good luck with your cannon project; it sounds like a good one.
What type of historical cannon do you like, by the way??
Mike and Tracy
Thank you for the information! I've lurked here for quite awhile and found a lot of great information. I've always been into artillery and cannon, specifically pre-Victorian and can remember annoying my father by demanding to pull over whenever I saw a cannon, and dragging him all over Gettysburg.
I've also read a great deal about Medieval cannon, specifically have a love for organ-guns, and other odd European stuff. The big cannon are fun, but I do have special place in my heart for the smaller ones, from Washington's 2pdrs at Trenton to the Robinets of the English Civil War. (The latter is a project I do want to build up and I think I have a recent photograph of one in England).
Back in College, I took a lot of woodworking and metal smithing classes, with a spattering of blacksmithing, though I can't yet cast up a barrel, I could certainly put together a carriage with enough time and creativity.
I have thought about half the fun being casting up round shot, or pouring up loaded cans of Portland, and I guess I have a good thing going with the strip mine being 2.5 hours away, so I have a lot of time to spend making sure everything's squared and up to date. But most of all I love learning more about this hobby.
Ultimately, I'd love to have a 10pdr Parrot or 3" Ordnance rifle, but I guess we all have to start somewhere.
I guess right now, I have a itch to scratch and really want to get into the hobby good and proper