If you page through Shumway's RCA v. 1&2, the best collection of early rifles for reference, you will find exactly one .40 rifle [#133] and three .42 rifles [#s 96, 119 and 135]. The majority of the rifles in this collection are over .50. If you page through Kindig's book on Golden Age rifles you will find a few in the .30s. Some of these existed in the late 18th cent and Lewis and Clark carried a .30s bore rifle on their long trek in 1804--that said, their basic rifles were .54s if I recall. I have put together stats on several hundred original rifles and the average caliber over a long time span was near .50. The average per quarter century beginning with the third quarter of the 18th cent [1750] decreases through time from the mid .50s to the mid .40s in the 19th cent. The overall spread [range of calibers] does not change much, small to large bores always being present in some amount. By the late 19th cent squirrel rifle calibers were quite common in the east and Bedford rifles so made lasted through the BP cartridge era. Southern mountain rifles also were in the 19th and even early 20th cent commonly made in squirrel rifle calibers.
This is a more complex subject than it seems. Its impossible to look at surviving rifles in general and get an accurate idea of original bore sizes.
These are all USED RIFLES.
They have been RECUT in almost every case. This is what is universally overlooked or ignored in considering bore sizes in ML rifles of the past. The bores were "cut out" as part of normal maintenance.
As previously stated there are early rifles that have been converted to percussion. They likely were used for 75 or more years just as flintlocks. Then converted circa 1835 and used for ANOTHER 50+- years. These rifles were expensive multi-generational tools.
Iron barrels tended to erode faster from hot gases than steel barrels so they tended to enlarge especially at the breech for a few inches even it carefully cleaned the bores still enlarged.
Rifles on the frontier were often left loaded all the time. They were not always perfectly cleaned (tallow is not a perfect cleaning solvent and could be corrosive in itself) since shooting something meant attracting attention so you better reload it ASAP. So they rusted. When they eroded, wore or rusted to a point where accuracy failed they were recut. Depending on usage and the expectations of the owner the bore could need freshing every couple of years. This meant enlarging the mould and often making a new breech plug as well if the threads were now smaller than the bore. This was all common work and is DOCUMENTED to the time.
The rifles used by the L&C expedition were likely 54 (many 1803s are now 58 or 60 caliber BTW). But nobody knows for sure and more importantly they were MILITARY RIFLES. There is no description of them other than the issue rifles being "short". At that time the British had put the 62 caliber Baker (1800) into production so the US needed a SERVICEABLE larger bore rifle than the not very serviceable miss-mash of 50 caliber Contract rifles. The result was the various 54 caliber service rifles developed from 1803 to the adoption of the 58 Minie.
Clark's personal rifle was FRESHED during the return trip BTW. So it changed bore size at lest once during its lifetime.
"April 7, 1806... Some little alterations all which were completed rectified in the Course of the day except my Small rifle, which I found wanted Cutting out."
"April 8...John Shields Cut out my Small rifle & brought hir to Shoot very well. the party ows much to the injenuity of this man, by whome their guns are repared when they get out of order which is very often."
He likely had to enlarge the mould as well.
I did a study of 281 rifles from the 2 KRA books, Flintlocks only from all time frames.
Of these 281 rifles and smoothbores (81) there were 14 in 44 caliber, 37 of 45 caliber, 60 in 50 caliber, 26 in 52 caliber and 21 in 54. All others were less than 20 specimens. 47 caliber 12 times, 48 caliber came up 18 times, 58-14 times. All others were single digits. Had I omitted the SB the data would have pointed to smaller bores more than it did. I did omit all fowlers and 1/2 oct smooth guns.
I will see if I can get the info into a readable graph tonight.
I seriously doubt that any of them retain their original bore sizes. Many rifles in good condition were freshed or bored and re-rifled in the 20th century to make shooters for the early NMLRA matches, read Walter Cline's book. So one must go back to the rifles that show little use and the WRITINGS of the time that mention bore sizes. Sparse as these are.
The next thing is EFFECTIVENESS vs AMMUNITION COST. In this the 44 to 50 caliber wins at least in the east.
Why shoot a 270 grain (58) ball when a 120 to 180 grain ball will work just as well? Then there is the powder needed for the heavier ball.
Most people in Colonial America were not very affluent and ammunition cost is ALWAYS a concern. This remained the case into the 20th century. The 1886 Win is often found in 40-65. BECAUSE IT WORKED as a hunting arm and the ammo was cheaper than 40-82 or 45-70 or 45-90. All of which were more powerful but the effectiveness was not greatly enhanced. Shoot a deer in the lungs with any of them and they die. Why pay for extra powder and/or lead? A 45 caliber RB kills deer just like a 54 does the holes are smaller but the deer still dies IF the shot is placed right.
If hunting deer in Kentucky in 1768 "without landowner approval" would a 40-45 caliber be better or worse than a 54? The 54 is going to require significantly more weight in ammo (which you have to pay for AND pack around) and MAKES A LOT MORE NOISE. If I were engaged in this I would use head shots where possible.
One other thing that we must consider is that the calibers listed for any given rifle sometimes changes depending on who is measuring them. So anyone studying bore sizes must consider recutting, reboring both during and after the rifle's original service life. And the fact that some people were apparently not as observant as they could be in measuring and/or detecting rifling traces.
Dan
