I must with respect disagree with the two references, which if viewed together without further information might lead some to think the "Tula" or jug choke was being used in the 18th century.
Marolles was plagerized word for word more than once in various "Essays on Shooting" in the English language in the 18th century. The text was verbatim.
What Marolles describes is actually a belled or coned relief at the muzzle and in this particular case it is also roughened.
Here is the Marolles quote from Greener's book......On the authority of M. de Marolles, who wrote in 1781, it is asserted that
choke-boring was known to, and practised by, the gun-makers of his day. He
writes : " An iron or wooden mandrel, fitting the bore, is furnished at one end with
small files, which cut transversely only. This tool, put into the muzzle of a barrel
and turned round by means of a cross-handle, forms a number of superficial
scratches in the metal, by which the defect of scattering the shot is remedied.
One effect of this plan is that of destroying the smoothness of the barrels within,
rendering them liable to foul, and causing them to lead sooner, after the discharge."
The part of the Moralles text that Greener leaves out (probably because of the Deyeux reference below which would make for redundant reading) is........Some make the barrel wider for three or four inches at the muzzle ; and this bell-mouthed form is of very ancient date. Espinar, whose treatise has been already mentioned, says, he has generally found this succeed in making barrels throw their shot closer.
Greener then quotes Deyeux from an 1830's text....... Deyeux, who published the "Vieux Chasseur" in 1835, writes : "I have seen these
results produced by a barrel slightly opened at the muzzle, choked in the centre,
and freed at the breech, such as some good smiths pretend is best to make them.
I have seen the same results by a barrel choked two sizes at the muzzle, and by a
perfectly cylindrical gun."
Deyeux, in his use of the word "choke" is to mean the bore itself is reduced in size from that of the breech and muzzle diameter and not "choke" in the sense of pattern constriction as we think of it.
It is hard to see some of this not be a jug type of choking by just reading text and having modern knowledge of shotgun choking but when you see the above described barrels in person it all comes together.
I have in my possession a barrel as described.
Many of the old fowling pieces were given that bell in the muzzle and some were also relieved in the breech as well.
Could a jug have been done in the 18th century? The technology was certainly there to perform the actual simple task but to my knowledge not one material example or documentation of same exists.