Cannon balls

[adrian]

Stone ball cannons had the chamber narrower than the bore.
Apparently this artillery system disappeared during the 17th century.

Interestingly this system, with a smaller diameter powder chamber, persisted well into the 19th century & was used with shell firing ordnance such as mortars, howitsers & some shell guns etc.

Regarding stone cannon balls, the Royal Armouries experimented with some stone shot from Mary Rose & demonstrated its ability to easily penetrate great thicknesses of timber representing the side of a ship, when recovered the shot was still mostly intact. So the use of lead covered iron shot is rather curious, I think that less wear to the bore than with iron alone was a definite benefit, many of the larger natures of ordnance on Mary Rose were bronze and iron shot would scour this badly, & I would surmise that the intent was to provide for a limited supply of heavier weight of shot than the stone shot.
Much later iron shot were of course used in bronze guns, but with a wood bottom strapped on (later rivetted on) to minimise bore damage.
Adrian

[fernando]

Glad to have you around, Adrain

Originally Posted by adrian

Stone ball cannons had the chamber narrower than the bore.
Apparently this artillery system disappeared during the 17th century.

Interestingly this system, with a smaller diameter powder chamber, persisted well into the 19th century & was used with shell firing ordnance such as mortars, howitsers & some shell guns etc...

Perhaps my approach was not a fortunate one. I was correlating the system of stone ball artillery along with wider chamber diameter. I could refer to stone ball artillery period ending, but would not mention the longevity the chamber wider than bore alone.
There is this work covering an historical artillery exhibition in the Oporto Military Museum, where the author brings about this chamber system which, around here, is called encamarado (enchambered, in a free translation) or releixo (relax), applied in cannons used on board artillery or siege operations, seeking to obtain the ammunition (pelouro) shatering, in order to cause (more) casualties. In this exhibition a XV century gross bombard, possibly Portuguese, was present with a caliber of 85 stone arratles (circa 40 Kgs = 33,5 cms. diameter), loading 25 arratles black powder, with a (useful) reach of 400 to 500 metres, with a +5º elevation.
Concerning the bore damage caused by stone balls, the Portuguese had the option to melt and recast their cannons every hundred shots, so possible as they had established fundries in Goa, Cochim, Malaca and Macau (Rainer Daehnhardt).