It is believed that the Model 1792 Contract Rifle was quite possibly the rifle issued to the Lewis & Clark expedition from the Harper's Ferry Arsenal for the Expedition of Discovery. Based on research in Man at Arms magazine by Frank A. Tait, and American Military Shoulder Arms by George Moller, a better picture of the 1792 Contract rifle has begun to be pieced together.
After the defeat of Major General Arthur St. Clair on the Wabash in late 1791. The Secretary of War, Henry Knox began procuring rifles for the army. After examining a prototype rifle, he gave approval on February 4th, 1792 for the first small arm designed specifically for the Army of the United States.
The rifle was to have these specifications:
42" rifled barrel bored 40 balls to the pound (about .490")
lock was to have a fly in the tumbler
stock to be made from well seasoned maple
catch spring release to be high so as to be accessible to the thumb.