Please remember that the men who went to the mountains to trap Beaver were not very literate- able to read and WRITE well. Their stories were written by "reporters", often in St. Louis, when these men returned every few years to the city. Some writers traveled with supply trains to the Rendezvous in the mountains and interviews trappers there.
Reference to "Hawken " rifles may have been generalized, making them seem to be the ONLY make of gun that went out there. Certainly, the movie, "Jeremiah Johnson" which hit the Theatres in 1973, spurs lots of interest in owning "genuine Hawken rifles", so we can blame Hollywood to some extent for much of the misconceptions.
From the Histories I have read over the past 55 years or more, all kinds of guns went to and over the mountains, used by both trappers, and explorers.
Guns that weighed as much,and therefore were pretty sturdy like the Hawken rifles made in St.Louis were admired for their durability, as well as their accuracy and power. But, these are, and WERE Heavy guns. Few weighed less than 9 lbs. and most more than 11 lbs. That is a lot of gun to be carrying unless you are horseback, and can let the horse do the work for you.
I recall rifles having been made by Henry, Hawkins, and Leman being mentioned in the histories I have. But, if someone made rifles between 1820, and 1850, at least one of them went West to the Mountains in the hands of someone. :bow: Because of the Gold Rush which began in 1949, the demand for rifles and shotguns became extremely heavy, and jump off places, like St. Louis, and St. Joseph, Missouri, Could, and did, sell just about any brand of rifle or shotgun made. All the Eastern Gun makers either moved West( Sam and Jake Hawkins moved their shop from Pennsylvania, to St. Louis) or arranged to have dealers sell their guns out there, with some guns becoming very common out West before they were available in the East.