The lads over on the theminiaturespage.com seem to be running this discussion into the ground. Spanish horse artillery 1808-1815: http://theminiaturespage.com/boards/msg.mv?id=531061
Obús-cañon á 8 M-1792 From the designer himself:
“Por consiguiente, serán mas oportunos para esta Artillería Volante unos cañones de a 4, y unos
licomes (1) u obus-cañon formando con los mismos cañones de á 4; pues esto s, agrandadas sus ánimas, arrojarán unas granadas del calibre de las balas de á 8, y la metralla del mismo calibre.
¿ Quien dudará que estas piezas serán las mas ventajosas para el uso de la Artillería Volante con nuestra Caballeria ?
Teniendo estos licornes y cañones de á 4 la fuerza y alcance necesario ó bien para desordenar.
(1) Licorne es un canon de menos, longitud ,y refuerzos que los correspondientes á su calibre destinado á tirar granadas y metralla. Los rusos, que les han dado el nombre, los usan de todos. calibres en lugar de obuses.”: https://archive.org/details/bub_gb_nW8LPwTy8IcC/page/n50
Some guy on the TMP Forum wrote in response to a post of my above post. "The Spanish artillery arm adopted the French Gribeauval System and so used the field pieces for both foot and horse artillery."
My disagreement with his statement centers on the word 'adopted'. The Spanish system used Spanish measures, not French. French ammunition could not be used in Spanish tubes because it's diameter was to large for the Spanish bores.
There are other differences. As my post above states, the words are those of the implementer of the Spanish 'Artillería Volante', said artillery used the M. 1792 gun-howitzer with the bore of an 8 lb. Spanish gun when formed in 1792. At a later date the French Gribeauval style howitzer, with a different bore diameter, was implemented by Spain.
The Spanish also used a 4 lb. [Spanish measurement] mountain gun with a much shorter barrel length. There were many other differences between the two systems. A copy of the 1993 reprint of Morla's 1816 plate and plate text vols. would be useful to Study the Spanish artillery of the 1790-1815 period.
Perhaps 'adapt' would have been a better word choice.
La Artillería Volante baxa a la prolonga acompañando a las Tropas ligeras por un Pais montuoso: https://images.skinnerinc.com/full/687/1065687.jpg