There are a lot of paint-on products for treating the cut ends of pressure-treated lumber. However all of the products that I can find are rated for above-ground use only.
PT lumber comes in "ground-contact" rated treatment, so you can place the lumber directly on the ground and it will take years to rot. It's expensive. But it really only works if you don't cut it and expose the untreated innards of the lumber.
Is there a product that is rated for ground-contact that I can paint on the cut ends of ground-contact-rated PT lumber?