i bought a 12 ft X 1/4" (I believe that was the original length) of air hardening drill rod from a local supplier. I used this to make a cleaning rod for my .29 Cal and now use it for my .32 Cal. I forget the cost but I couldn't believe how cheap it was, $5 to $7 if I remember correctly.
Its pretty hard just as it comes and I am a firm believe that the harder the cleaning rod is the less abrasion you will have on your bore. The crud from the barrel will embed in the brass rods and is less likely to with the harder steel rods. In my center fire benchrest days we found that even with use of a bore guide the cleaning rods would bow in the mid-section and over time would wipe out lands in the bore, usually around 1000-1200 rounds. These were 6MM bores but I suspect .25 and .32 bores are still small enough to have the same problem from cleaning rod abrasion.
Dennis