Stiff Western Saddle Rope, Nylon, ~100ft, Pre 1956

I've had this for ~25 tears or so, picked up at a local barn sale. The tag in pic 8 was with it. I hung it an' forgot it 'til a week ago, dug it out, blew the dust off it an' shot these pics.
It is ~3/8" diameter; both ends are finished the same way. The coils average 19" in diameter; there are 19 of them, plus whatever length is in the securing wrap...I figure there's 100 feet of overall length. I have no good descriptive word for how stiff it is; though obviously flexible, it's hard as a board, very tightly wound...perhaps around a stiff core of some kind.

I found this Brief Life History of Helen Louise Milliken online, at Family Search:
"When Helen Louise Milliken was born on 3 June 1906, in California, her father, Henry Milliken, was 22 and her mother, Catherine Howell, was 22. She [Louise] had at least 1 son and 1 daughter with Miller Harrishouser Hurt. She lived in Riverside, California for about 20 years and West Riverside Judicial Township...in 1940. She died in June 1956 in Riverside, San Bernardino (County)."

I don't know much about Western horse gear, but find this to be curious enough (with its scant provenance) to be, perhaps, of some historical value, particularly local to Riverside, CA. I'll be grateful for all your comments an' suggestions...especially about how it may have been used. I believe it is too stiff to allow a hondo or lasso knot to be tied on one end...bicbw. Thanks for lookin'!