This is probably one of the harder questions to answer that I have seen posted here, Rhbrink. A lot of what I am going to say here is just my theory, so don't take this a anything backed by years of research.
I am of the opinion that many rifles were made prior to 1780 that were less than 50 caliber. In fact, I think it could have been a slight majority that were less than 50. There are several reasons I believe this. First, much hunting done in the 1760s and 1770s was done for small game. It is a romantic notion that everybody went out looking for deer and elk. But that ignores the fact that these people were not wasteful, and on the contrary, quite frugal. This meant in all ways... Lead and powder were more expensive compared to today. Smaller bores meant more shots. Also, a smaller bore was probably a less expensive gun. Considering that at the time, the price of a new rifle was about half the average annual wage at the time, it makes sense smaller bores would have been used by most of the people. Additionally, most families could not finish off a deer in a week, and though there were methods of preserving meat at the time, it would have been more of a winter time activity to go for deer, when the weather was cold. It is well documented that domestic animals (excluding chickens) were slaughtered in the fall, so that preservation had a better chance of success.
We also have good evidence that many of these early rifles, once the rifling was shot out, were re-bored and re-rifled. This would also indicate that those we can study are not of the original, smaller caliber. Some rifles had this done several times, depending on how heavily they were used. Which is another point... The more a rifle was used, the more likely it is that it didn't survive for us to be able to study it. Of course the larger bores were out there, but I believe this was more common in fowlers and muskets. Once the Kentucky territory became a popular hunt, bore size probably increased due to larger game like elk.
Back in my younger days, I used to live in the sticks and hunted all of my own meat. That was rabbit in the majority. Every shoot a rabbit with a 50 caliber with a body shot? Not much left of it, and not much hide to tan. I used to take head-shots with a 45 caliber, and that was a little overkill, but worked well for me. That was an old Italian-made cheap ML too... lol.
Just my opinion though. Would love to hear any arguments to the contrary.
Matt
