You can read through the other posts here,,as I have,,and I don't remember seeing any replacement rods offered that will fit under the barrel.
You could buy a one piece range rod,,which is fine,,but I don't see anyone carrying that around while they're hunting. The factory rod is all thats available because of the barrel/fore end stud. And really,,I don't find it all that bad. I did make an attachment out of a solid round 3/8 brass,,2 inches long and tapped 8/32 on one end,,with a brass machine screw inserted to adapt to the factory thread. Then tapped the other end 10/32 to accept the numerous attachments out there for sale by other companies for cleaning purposes.
The collapsible rod works okay for what it is meant to do in the field. I guess I sort of like the theory of "one shot ,make it count".
And that is likely why we here continue to buy and enjoy shooting H&R/NEF firearms........