Stan,
I understand that in black powder days the smaller the bore the quicker fouling build up became a problem.
This is why the Lancaster Oval Bore and Holland’s Semi-Smooth Bore Rook Rifles were promoted for their abilities to fire multiple shots without the need to keep wiping out.
Early Rook Rifles were often .380 and could also be used for Roebuck, Duiker and other small quadrupeds.
Just to be clear a Rook is not a Crow although a similar bird in the Corvid family. Their habits are very different.
Rooks are very gregarious and build their nests in dense colonies called Rookeries (a word also used in Victorian London for a Criminal slum at St. Giles).
This and the fact that the breast meat of the young “branchers” was edible if properly marinated (Mrs. Parabola has cooked a Rook Pie) made Rook Shooting in early May, when the branchers were emerging from the nests but there was not yet too much leaf on the trees, an annual social event when there was not much else in the way of shooting on offer.
The gentry would gather for a house party with single or sometimes double rifles from best London “makers” almost invariably from a Birmingham supplier.
For Rookeries not reserved for their “betters” the villagers would harvest the branchers with catapults, shotguns, stone bows etc.
As American .22’s were imported and ammunition improved .22 rifles generally displaced the centre fire rifles.
I the 1895 Army and Navy Catalogue the .22 Colt Lightning was offered as a Repeating Rook Rifle.
[img]
https://i.imgur.com/8mcGMcW.jpg?1[/img]