I think that if you seperate what are commonly accepted to be some of the earlies surviving rifles, these seem to have larger bores than later examples. For example, RCA 142 (68 caliber), Marshall rifle (possible re-used barrel, 58 caliber), Schreit rifle (60 caliber), Musicians rifle (58 or 60 caliber I believe), RCA 118 (55 caliber), Faber rifle (60 caliber).
I think this is sort of analagous to the common statement of "original barrels having much less swamp than modern reproduction". There are many times as the number of surviving later guns than these earliest few. Again, I think the time period must carefully be considered.
Jim
The subject requires RESEARCH. THEN a conclusion. Most people have done this backwards in regard to calibers.
As I stated the accepted dogma is often WRONG. When we discuss bore size as "larger in the early rifles" we have to ask larger than what? A 1850s 30 caliber squirrel rifle? A 50 to the pound Golden Age rifle? Gen Ashleys 69 caliber Hawken? Ever THINK about WHY he might want one of these? I have a theory. He sure did not need to to hunt with. But it would shoot 300 yards off a keelboat with more authority than a 50 or 54 if the natives were unfriendly. A valid reason for a 67-72 caliber rifle in Colonial America as well.
I keep wondering about the 1757 inventory of Indian Goods at Rock Creek
"abt 1 dzn 4ft square [octagonal; a common mistake] barrel'd Guns very small Bores- best Iron mounted & stocked like Rifhells..."
Now I have to wonder what was a very small bore for a smooth rifle in 1757? 42? 44? 50? 54? Nobody knows.
What size were the rifles in the next entry?
It is obvious that small bore guns were known. It would not take long to determine that it did not take a one ounce ball to kill game.
Given the economics, as mentioned in the 1760s, the large bore guns would have soon been seen to be an unnecessary expense for people of low income. I have friends of my generation that tell me of shooting deer with 22 rimfire largely because it was CHEAP or it was what was in their hand when the came across the deer. If you needed meat and it was not hunting season the 22 is a far better idea than a 30-40 Krag. The sound indicates a different purpose if its even heard.
We have a thread on this site with a photo of a BOX FULL of freshing tools, but we don't want to think that the 58 or 60 caliber rifle we want to recreate might have been freshed 3-4-6 times over its 100 year service life and started out as a 50. This gores the cow.
The Marshal rifle was likely freshed, the Schriet maybe not, it was in Europe after all but it may have been shot for 20 years previous to "migration".
Its not an easy topic to sort out and to most people its not important. Its like detailed barrel dimensions, rifle weight and rifling pitch. Collectors, in general, are not interested in these. But I am.
When we consider calibers of long rifles we need to do more than look at surviving rifles listed bore size (which can very significantly depending on who looked at the rifle. These are only a PART of the picture. A clue. There are other clues that are just as valid if not more so.
THEN we have people like Cline reboring and freshing original rifles, flint and otherwise, in the 20th century to "improve them" as shooters. Bill Large freshed or rebored a lot of originals.
How does THIS effect the caliber discussion? I submit that is very unlikely that a Kentucky built in 1775 and then used to any extent still has its original bore size even if it was never bored smooth.
Dan