If you read what I had written, you will see that i asking how did period observers actually know what was happening to the cannister round in the tube given that a) they could not see it B) due to this any conclusion was suppostion.
How can you make an imperical statement of fact about an event you cannot see?
Period sources on how a cannister worked is informed guess work at best. They knew the effect of cannister as that could be observed, BUT they did not know how that effect was brought about. period commentators were merely guessing.
Another anaology. The Greeks believed as did most of the educated world till fairly recently their was nothing smaller than the atom and the atom could not be divided. Modern science shows it can. I beleive my horse analogy to be fairly accurate regarding how supposed 'fact' from the past is prooven wrong by modern imperical observations.
Twenty period sources can offer their opinions on to how a cannister round, but they cannot offer fact on how the cannister ruptured in the gun tube. Their is a difference between opinion presented as fact and imperical data gained from observation.
All I am saying is, how did the period oberservers know for a fact how cannister ruptured in the gun tube? to my mind they did not know imperically what happened, if you can offer hard imperical data on how a cannister ruptures I would be pleased to red it.