Something might help, if you're not already doing it. Apply the Proofide under heat. Not a lot, but melt that stuff down into the leather, and apply more. Proofide is a mixture of oils suspended in waxes, so it's designed to sit near the surface of the leather, thus protecting it but not over-softening it. If you "melt" it in with a hair dryer or carefully used heat gun, it will penetrate more deeply. I have a barely used Pro model from the early 70's. It's hard as a rock. It was built that way. I don't mind and just use Proofide on it once in a while.