Dating of chambers for breechloading cannon

[fernando]

I regret that no sources show up to provide some information on this theme; perhaps because it is so specific and not so much explored.
I have to contact some local specialists in artillery but unfornutaley one has his email disabled, the other is deceased and for te other i dion't manage to ge his contact.
I here attach pictures of two early pieces; one a 'cão' (dog) from the end 14th beg.-15th century, in exhibition in the Portuguese Navy Museum and the other, his successor, a 'berço Manuelino' (so called cradle of King Dom Manuel) circa 1500, from the collection of Riner Daehnhardt.
Although they have not measurements notes, one can see that proportionaly their chambers are not that narrow nor that long.
I am not sure that the second chamber belongs in the berço but, if not, the period will be the same.



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