Chasseur,
The truly classy answers are ebony or rosewood ramrods. I have an original rosewood ramrod on my Lang double and it is at least 175 yrs old and still good as the day it was made.

The brass idea uses very thin walled brass tubing that I buy in 3 ft sections at a hobby shop. I used three nested tubes but 2 would have sufficed. Solid brass would be way too heavy.

Brent