This is just my humble opinion but here it goes.., ?
If you want to build a golf ball size bore..., many do.., then you'll need a 5.25 breech.., most dont do that..., but thats the right and safe way to go...., I think .., I am no expert.., I am but a humble enthusiast . So....., again I opt to go with less bore. perhaps instead of giving up on CCC or going with a steel (That is if you really want the golden gun) then perhaps bore reduction is in order? A 5.250 breach is actually a pretty heavy gun to move.., lets consider that too for a moment. Bill will build what dimensions you request and will adjust the cost accordingly to the metal. I chose the bronze tube......, sure its a bit tough to swallow......, but then again., it lasts ...., and lasts..., and last...., and ? Your great grand children willl be fighting for it...., at least thats what i am hoping for..., lots of disgruntled family mayhem long after I am gone (I may possibly be in some arguements 100 years after I am gone...., i like that., Its in my nature) . there is nothing wrong with steel ., I have 3 steels ..., since they were cheaper ., I went huge ! but I cant afford Huge in a metal that's 85% copper !!! So ..., bore reduction. Actually Civilcannon I am in the middle of a 6 cannon project ., with 4 inch material ., and it was asked of me my reasoning for not going to a golf ball bore......., well the reason is because there just isn't enough meat on 4" stock to justify a bore that big and I have to stay under a certain weight to ship these cannons after they are finish....., so we chose a bore that works safely.
With Bore reduction you get a smaller breech ., easier to move and handle., and cheaper to upgrade to better material ., savvy ? Another manufacture is going to have to either get your breech / bore measurements either right or wrong as well...., so its really a matter of what measurements you request. Any particular reasons for firing golf balls? The 1 1/4 bores were really started because you could use film containers full of concrete....., however with the digital camera ., film really isnt coming back., so that particular bore size doesnt really have a cheap projo logic to it anymore either.
My reasoning for 1" bores are I can use a "Do-It" fishing mold for a 3oz sinker at 34 bux for the mold. 3 oz sinkers provide plenty of recoil ., and the other shooters at the range with AK's and 30/30's are shocked at what my gun can do....., and is sets up quik and it loads quik ., hits hard ., and is loud........., Bronze has its own unique sound as well. If your interest is in LOUD signal firing ., then obviously the 1.75 is louder that 1.00 however I have been next to a man firing a golf ball..., and my 1" firing lead is louder ..., I believe that is also another effect of pushing lead......., it doesnt take much pressure to move a golf ball. For example ., my Beer can mortar is much louder again., as a can of concrete is heavy and the powder charge has to become pretty violent in order to lift that concrete ! . Lud volume changes with bore size...., it also changes with projo weight..., however a signal can be fired anywhere ., a projo requires ALOT of room.
This is just a little food for thought.