I not sure about the idea of a "snug fitting stick" but do recall the reference of mountain men carrying a stick in the bore of their guns as a spare--and there is good reason for it. Hard wood suitable for making ramrods did not grow in the Rocky Mountains. Below is an image from Wikipedia showing the natural range (in green) of the hickory tree. It only reached the extreme eastern portion of today's Kansas and Nebraska. In 1841, Rufus B. Sage, who hired on with Lancaster Lupton, the owner of Fort Lupton on the South Platte River, wanted to go West and write a book about his experiences. While traveling with Lupton, Sage kept a journal of the trip West. Eleven days out of the Independence/Westport area, they came to the Big Vermilion, a tributary to the Kansas River. At a "dollar apiece" one can see how valuable an extra ramrod or wiping stick was to a trapper. Council Grove on the Santa Fe Trail was another place that travelers stopped to collect hard wood as it was the last place on the Santa Fe Trail that trees such as oak and hickory grew. Santa Fe caravans would cut logs suitable to repair broken wagon axles and other wagon parts and strap them under their wagons. Hickory would have been gathered for hatchet and axe haft repairs as well as replacement ramrods. While looking for first hand accounts of use of trade rifles and trade guns, I came across this sketch that Karl Bodmer made in 1833 of an Assiniboin Indian in the vicinity of Fort Union. Note the Indian is clearly carrying a Northwest trade gun that has a ramrod in its thimbles. He is also holding an extra wiping stick that appears to have some material or tow wrapped around what is likely a tow worm. Trade guns and rifles were often ordered by the fur companies with wool covers, bullet molds, and wipers or wiping sticks. Carrying the wiping stick or extra ramrod in the bore of the rifle or trade gun would have been a handy and practical place to carry it. I doubt that they provided a snug fit, but their mass and weight would help to keep a ball on the powder. If they were marked near the muzzle, a person could tell at a glance if the ball had moved off the powder.