Hi David,
I happened to have some notes on hand from research a while back on leather cannons.
A reference titled "The Army of Gustavis Adolphus" Vol 2 (p.17) Richard Brzezinski, 1993 notes, "...the leather cannon was superceded in 1629 by a weapon that did not have the same tendancy to overheat and burst". The new version was small and bronze apparantly.
It seems that the first leather cannon was from Zurich c.1622 and an Austrian baron took them to Sweden c.1625.
In Polish Prussia 1627 there were 14 of these leather guns, last recorded use 1629.
Gustavus Adolphus had sought a lighter weapon with mobility to serve between the musket and stationary cannon. These were thin copper tubes strengthened by heavy ropes and finally clad in leather, alternately in leather straps then rope.
Unfortunately the reinforced material would not let the heat dissipate, and the heat from detonation would deform the barrel.
While an unusual premise, it does seem there were some successful leather cannon used by the Venetians, also mortars. There were leather cannon captured in campaigns in Nepal c.1792 as well, and while I cannot find the remainder of those notes, it seems that leather cannon were used by Chinese forces in those times in some degree as lightweight mobile artillery.
A type of leather cannon was fired successfully in Edinburgh in 1788 (I believe this was from "The Gun and Its Development" WW Greener, 1907).
Interesting topic, and I wanted to add these notes while looking forward to the Maestro's comments
I'll bet Michael even has one of these!!!
All the best,
Jim