Hi David,
Thank you for considering me.
I think Jim put it so expertly that I cannot add anything substantial. We know that leather cannon existed so they must have stood the shooting. Personally, I can hardly imagine that but I am neither a physicist nor an engineer.
And Jim, thanks a lot for overestimating my collection!

Actually I do own a small cannon which is illustrated in a few pictures of my collection posted here some time ago. The 15th c. barrel is of bronze though. I am preparing to post it in a thread of its own.
Best,
Michael/Mikhail/Michl