I do not appreciate hardwood or fiberglass rods. Regardless what testing appears to show, I am convinced that rod material, and firing residues on-and-in the rod, will abrade barrels abnormally at muzzles.
I no longer use thimbles beneath my Kodiak Safari rifle to hold its [plastic] loading rod. Recoil causes the rod to move muzzle-ward between six and eight inches with the first shot. It then waves and vibrates. . . . Not beneficial to continuing consistency from a regulated double rifle. Solid surface hardened stainless steel rod solves the abrasion problem but does nothing for recoil induced rod movement.
How have those of you who shoot BIG BORE rifles with heavy loads deal with recoil rod movement I have tried to describe? I have considered using hollow rod, or hollow titanium alloy rod, or fluted rod - that is, reduce rod weight by deleting metal while retaining rod hardness and rigidity. But I don't believe such a rod is available.