Why? What horrors would befall you if a range / trail rod broke?
FWIW I made several trail rods out of basic / generic wood dowel from Home Depot. Never broke one. It is probably all in how you use the rod. Go straight in and they will never break. Twist the thing around in an arc as you ram and maybe it will break.
A solid bronze rod would be both expensive and friggen heavy. I would def NOT want to have to carry such a contraption around.
This all strikes as making a mountain out of a molehill, based on some intangible, " don't trust it" which is based upon nothing but feewings. There s absolutely nothing wrong with a wood dowel range rod and the world won't end if you break one.
You are going to spend all kinds of money and effort and time solving a completely non-existent problem. Have fun with that.