Guns change over time, sometimes fairly quickly, so it's interesting to see a sort of snapshot from one brief period. Here's a description of flintlock rifles as seen through the eyes of an Englishman traveling in the western US, east of the Mississippi, in 1822-23.
William N. Blane _An Excursion through the United States and Canada, during the Years 1822-3_
[caliber conversions are mine.]
"This is the only fire-arm used throughout all the Western States, and is generally from three and a half to four feet long in the barrel. It has one turn in four feet, weighs from twelve to fourteen pounds, has a very small and crooked stock, and carries a remarkably small bullet. The great weight keeps the gun steady; and the charge is so small, that one might almost balance one of their rifles across a gate, and fire it without its falling, the recoil, if any, being so imperceptible. The usual size of the balls for shooting squirrels and wild turkeys, is from 100 (.36) to 150 (.31) to the pound. For deer and bear, the size varies from 60 ( .42) to 80 (.39), and for larger animals, as the buffalo and elk, from 50 (.45) to 60 (.42); though a rifle carrying a ball of a larger size than 60 (.42) to the pound, is very seldom made use of. For general use, and for shooting at a mark, the favorite size is from 60 (.42) to 80 (.39)."
Spence
William N. Blane _An Excursion through the United States and Canada, during the Years 1822-3_
[caliber conversions are mine.]
"This is the only fire-arm used throughout all the Western States, and is generally from three and a half to four feet long in the barrel. It has one turn in four feet, weighs from twelve to fourteen pounds, has a very small and crooked stock, and carries a remarkably small bullet. The great weight keeps the gun steady; and the charge is so small, that one might almost balance one of their rifles across a gate, and fire it without its falling, the recoil, if any, being so imperceptible. The usual size of the balls for shooting squirrels and wild turkeys, is from 100 (.36) to 150 (.31) to the pound. For deer and bear, the size varies from 60 ( .42) to 80 (.39), and for larger animals, as the buffalo and elk, from 50 (.45) to 60 (.42); though a rifle carrying a ball of a larger size than 60 (.42) to the pound, is very seldom made use of. For general use, and for shooting at a mark, the favorite size is from 60 (.42) to 80 (.39)."
Spence