There was an article in the backwoodsman's journal a few monthes ago about it. They really can kill large game.

The one lewis and clark had was a 50 caliber is what they said. There wasn't much writen about it because when they were about to leave on thier journey, the local "news" folks were asking what kind of gear they would be carring.
There were quite a few people around and when they got to the air gun it went off and the compressed air blew a woman's hat off so they put it away. That story is about the only thing writen about that piece of gear.

"Hey ya'll, watch this"