Seems to me the original Lewis and Clark air gun had a round reservoir underneath the lock and was .30 cal.
Davryl,
it was long believed that their air rifle was made by Lukens, was a .31, and was likely the gun on display at Virginia Military Institute museum. but fairly recently actual correspondence was uncovered that clairified the situation, and made it likely that only a girardoni repeater could have fit the description.. American Rifleman published an article that included the original sources but this is the gist of it:
" The 2001 publication of the journals was popularly received by the large community of Lewis & Clark aficionados. Among those writing about the firepower of the expedition was a staff editor of Gun Report, Michael Carrick. Carrick delved into the journals, read all 13 volumes and made copious notes on any mention of the firearms used on the expedition.
Through a conversation with a fellow Lewis & Clark historian, Carrick was introduced to a most extraordinary manuscript, the diary of Thomas Rodney. Rodney was the brother of Delaware's Caesar Rodney, a signer of the Declaration of Independence. In September 1803, he went west to assume a judgeship as an appointee of President Thomas Jefferson. On Sept. 8, 1803, Rodney's and Lewis' paths crossed in Wheeling, Va. (current West Virginia was then part of Virginia). And Lewis made note of the meeting in his journals.
Capt. Lewis. Sept. 8,1803. ... dined with Colo. Rodney.
Fortunately, Rodney was a bit more verbose about the encounter.
Thomas Rodney. Sept. 8, 1803. Visited Captain Lewess barge. He shewed us his air gun which fired 22 times at one charge. He shewed us the mode of charging her and then loaded with 12 balls which he intended to fire one at a time; but she by some means lost the whole charge of air at the first fire. He charged her again and then she fired twice. He then found the cause and in some measure prevented the airs escaping, and then she fired seven times; but when in perfect order she fires 22 times in a minute. All the balls are put at once into a short side barrel and are then droped into the chamber of the gun one at a time by moving a spring; and when the triger is pulled just so much air escapes out of the air bag which forms the britch of the gun as serves for one ball. It is a curious peice of workmanship not easily discribed and therefore I omit attempting it. "
i corresponded with Dr Beeman, the air rifle man, about it and he put me in touch with mr Cowan who made the reproductions, and we had a couple of very nice long telephone conversations about it. at the time he was just finishing the project..... i could have gotten the complete setup for about 26,000.00 prepaid back then...i would have loved it but thats too rich for this man. Dr. Beeman had the gun which may well be the lewis and clark gun, as it has a repair to the spring that matches the repair mentioned in the journals, as i understand it.