Arnie may still have some , have not talked to him for a while.
His name here is beltfed. Send him a pm.

Grainger has acetal Delrin rods at 48" long.

I recommend Arnie’s ( Beltfed). He threads both ends 8-32. Last one I got from him was $25. That was a face to face purchase so I suppose you’d have to pay a little for shipping.

I’ve made many rods out of Delrin, shaft and knurled handle fixed with a dowel pin. Some have groves to grab the patch some drilled and tapped for commercial tips  Think the first one was wood scrapped round for a muzzle loader I built in High School metal shop 60 + years ago.

Others, larger sizes for shotguns, wood from hardwood dowels with fancy turned handles. Most used with vintage guns, Delrin would not be appropriate.

Never shipped or sold one, all given to friends and shooters at club matches. I’ve seen Beltfeds, there very nice and good value, buy one of his my advice 

Boats

Delrin is the material.

More than 6 types of Delrin brand plastics. Pull up McMaster Carrs web site and search “Delrin” dozens of options strength abrasion resistant shapes etc.  Also lots of Delrin copy’s, I only use the Delrin brand

One Delrin job I did was Re-bushing the steering linkage on two 45 year old ex Coast Guard 41 foot Utility boats. Linkage holes worn oblong. Dealer supplied 1 1/2 inch high strength Delrin rod. Enlarged the holes and turned new bushings. Boats operator worried they wouldn’t last. Gave him an extra bag for each boat. 3 years later no sign of wear on the bushings. Extras still bagged 

Boats