Not looking to start anything here, but could it be that some builders just don't understand why some folks here on this board keep insisting that the rules of an obscure group of Civil War re-enactors are the be-all and end-all of cannon design?
First neither the North South Skirmish Association nor the American Artillery Association are obscure or reenactors. The are a group active shooters who have been shooting live fire black powder artillery for many many years. They are not reenactors. Anyone with any experience or knowledge in the filed of live fire black powder artillery in the US is very much aware of them and their work. They have years and years of laboratory testing and live fire under their belts. The N-SSA is the preeminent authority of shooting black powder artillery in the US and in my experience are recognized world wide. By the very nature of your statement you show you have limited or no experience or knowledge in the field so I can understand why you would think them obscure.
There are many people out there that know for a fact that 1/2 inch thick steel walls with a properly constructed breech plug will withstand any reasonable charge of cannon grade powder. (with a correctly sized ball). I understand someone wanting to err on the safe side, especially when it comes to possible liability issues, but facts are facts.
You are wrong when you say "many people out there that know for a fact that 1/2 inch thick steel walls with a properly constructed breech plug will withstand any reasonable charge of cannon grade powder."
You would be correct to say, "many people out there
think that 1/2 inch thick steel walls with a properly constructed breech plug will withstand any reasonable charge of cannon grade powder. That is simply not true. Not all steels have the correct characteristics. Not all steels can stand the pressure.
With the correct steel you can indeed make a cannon with 1/2 thick steel walls and safely fire the gun. You statement would also be correct if you said, "
some people out there know that with the
correct type of steel 1/2 inch thick steel walls with a properly constructed breech plug will withstand any reasonable charge of cannon grade powder.
There lies the problem. Not everyone understands the metallurgy or the type pressures involved and I suspect you are one of them or you would have never made the statement you did. Please forgive mw, if you are knowledgeable, you just don't come across that way.
Many many of the people who come here do not understand the the differences of the type of steel and constructions. When you say facts are facts it is obvious that you are one of those persons. That is a fact, or you wouldn't have posed you question as you did.
In order to keep things safe we talk to the least experienced person who comes here. Absent any other credible source we point to the safety standards of the N-SSA as the guidelines for safe cannon construction. It would be irresponsible for us to suggest otherwise.
Up until the American civil war, with few exceptions most muzzle loading artillery followed very closely this one caliber wall thickness rule. After the Civil War advances in metallurgy along with the advent of of smokeless powders resulted in design changes including lighter thinner strong barrel steels.
We have advanced students here and they are building breech loaders of the type made after the civil war and prior to 1899 with lighter thinner barrels. They also posses the special knowledge to under stand what steels to use to be safe.
It is very easy to identify who is knowledgeable and who is not. We will always err on the side of safety and offer our guidance to the less knowledgeable. We are acting to protect our hobby because every accident puts us in a bad light.
Keep in mind that this board is about pre 1899 black p[owder mortar and cannons and their replica. It is not about making and shooting a tube full of black powder...