The Jaigarh Fort and its cannon ...

[fernando]

Originally Posted by Philip

... Tartaglia's studies were also the bases for the invention of several devices for the accurate aiming of cannon, the most important being the gunner's quadrant, which had a service life of over 3 centuries, and which is depicted in military manuals and art from as far away as India and China...

So Filipe, it makes sense that, in a coincidental period and as i quoted above General J. Manuel Cordeiro in his "Apontamentos para a História da Artilheria Portugueza – 1895", gunners in North Africa were already familiar with the quadrant, besides other abilities.
At this point a parentheses should be open to remind that, in this ongoing period gunners, as well as foundrymen, were increasingly required in a number far greater than what the nation could provide, for the need to import them from other countries was obligatory. There were highly qualified Germans, Flemish and others. At a certain stage Germans had a brotherhood, São Bartolomeu de Lisboa, were thousands of them were inscribed. More than a thousand have fallen in the battle of Alcacer Quibir (1578).

Originally Posted by kronckew

...They also made use of wedges, and with spare pre-loaded breeches, could maintain a certain amount of rapid fire. I imagine they were rather unpleasant to stand next to as they must have been fairly leaky when fired...

Wayne, You are right in that the cadence of fire was an asset that largely compensated breech loading flaws.
... And mind you, whatever collateral issues could arise from an 'ancestral' berço like the one in that tube clip, may not be compared with later ones in bronze, improved during evolution imposed by King Dom Manuel, where materials and metallurgic accuracy would achieve a better plug sealing. Also there was no need to stand by the gun side. The one gunner stood safely behind it, at a distance provided by the gun aiming 'tail' (tiller).
On another hand it appears that, the guy shooting the various loaded breeches in that clip, introduces the (simulated) projectiles into the vases, which is a recurrent false case. They are instead stuck into the barrel chamber. All that the breech takes is a gunpowder load ...eventually sealed with wax.

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