Exactly, during the fur trade the eastern guns wernt big enough. Mainly small bores, some were rebored to larger caliber but the stock designs were weak in the wrist area.
The hawken though was the cadillac of them all, heavy built rifles, accurate, reliable, big calibers. They didnt come with a 5 foot long barrel.
Back in those days, with the kentucky style rifles, they thought they needed a long arse barrel to be accurate, Not true!