I don't use the wood original ramrods. I use a working rod, nice and heavy. The wood ramrod is mostly ornamental. To keep them from creeping out with recoil I use a set screw. The ramrod guide or 'thimble' has a hole that is just right for a 1/4-20 tap. You can get the short set screws at the hardware store, brass or blue or make your own from a bolt. Fit them so they are flush. The rod won't move at all.
Or, you can make a stiffer retainer spring from an old set [or new] of automotive points. They already have the hole, just trim to length and shape