In my collection the rifle calibers vary between .32 and .58
The average being .47 caliber.
For the "Plains Rifles " / "Mountain Rifles" / Western Fur Trade Rifles , in my collection the calibers are :
.45 takes a .454 round ball / .50 ( x3 ) takes a .490 round ball / .53 takes a .520 round ball / .58 take a .570 round ball
I do have a St. Louis rifle made by a company associated with the Western Fur Trade in .32 caliber...
It was probably made for the local trade...and not meant as Plains or Mountain rifle.
Andy
Is there any correlation between the caliber and the region/game or was it basically just personal preference of the trapper?