I can not locate the article in which Calvó defines the
BOCA DE CABALLO as having started prior to the 1728 ordnance model. The source where i have read that, was a different one (which ?). Actually Calvó attributes the reason for the popular term to have been expessed by his friend Eduardo Jiménez. Actually my idea for such reason is not the same, as i feed my fantasy; but that is another business.
If i may express a (second) personal opinion, i don't like to use the term "bilbo", and neither do the Spaniards, i guess. I take it as a "foreignism", not the real thing.
Who was him who said:
" The current theories place the origin of the name to the city of Bilbao, in the modern Basque Country, in northern Spain, the capital of the actual province of Bizkaia which was a millenary iron-production center and also origin of sword and dagger hilts of fame at that time. It was a part of Spain with traditional trade contacts with Britain, so it's a very likely origin.
But fact is that the term is actually used to cover all double-shell hilt swords, and it's specially used to describe what in fact it's the Spanish cavalry Pattern sword M1728, like these:
This style was in use, with variations, since mid 17th c, and after being made into a cavalry pattern in 1728 was going to be in service until the beginning of the 19th c. As such, calling this a "bilbo", it's stretching the term a bit too much. In Spain it's called a Cavalry sword M1728, a "double shell" guard sword or a "Horse-mouth" guard sword, because of the similarity of a construction detail of the hilt with a piece of a horse bite.
"Bilbo" is an English catch-all word used to very generally refer to the Spanish "Utilitarian" cup-hilt swords, so often found all over America. They usually had a wide, _relatively_ short sturdy and well tempered blades, very practical and unadorned. The grip was more often than not wood, sometimes covered with wire.
The term comes from the Spanish Basque city of Bilbao, where a significant number of them were made and exported to the New World. In Basque that name is actually "Bilbo", although there's also a basque town by that name. I understand these swords were also sold to merchants of every european nation, including England.
The type was very popular aboard ships, where it was used on a similar role as the cutlass was among other nations. Needless to say, this sword was also used in Europe, but curiously, seem to have survived better in America. Probably because in the colonies these were better taken care of, since they were more difficult to acquire, and thus more valuable.
"Bilbo" if often misused by neophytes to refer to *any* spanish sword ".