Colonial Rifle Smith, Was curious where you read about burn striping Native American arrows? Heating wood can plasticize the lignin to help stiffen it. Pressure by "boning" to compress the cellulose fibers of wood will stiffen it too. Heat with grease is used when straightening an arrow shaft and can be used on the isolated weaker crook of arrows and ramrods, never in a useless spiral pattern. The grease penetrates the fibers to deepen the heat penetration and helps prevent scorching the surface as well.
There is archaeological evidence of the existence of paired grooved stone blocks possibly for heating and straightening arrow shafts. Some coarser grained blocks were used for sanding the shaft to a uniform diameter. These technologies for arrow straightening can be applied to ramrods as well. Some tool and axe handle manufacturers advertised "flame tempered hickory or ash handles" as a selling ploy.
In my study and replication of Native American arrows there were many Plains style arrows with cut or indented and often painted "lightening" or lightning grooves on the shaft. Some straight and wavy. From experience they do little to help keep them straight. Cut grooves are future sites for splinters. Arguments on actual origin and function of the grooves but some theorize they were for magic or decoration.
Soaking a hickory ramrod or buggy whips in coal oil or kersosene was to make them pliable and less prone to breakage. One author suggested the slower rate of twist on the decorative spiral on the rod echoed the twist in the rifling of the barrel. So long ago when I read it would be a chore to find. Maybe from Turner Kirkland's Dixie catalog. I would soak only after and not before flame striping.
Fire hardening the point on a survival spear is better done over coals and not charring over flames which weakens it. Of the many methods, potassium permanganate staining, leather dye staining, burning exposed wood with torch between protected masking or burning with a nitrated string, I find they serve more of a decorative function than to protect or strengthen the hickory ramrod. Doesn't seem to harm the rod if not overly aggressive with the surface charring.