Have you ever shot a patched round ball or a wad under a bore rider or a paper patched bullet. I have and I have recovered the patches if the patches fit tight there is NO gas cutting and the middle of the patch is not burned up. What is this patch ? It is material I cut from a pillow case and lubed with candle wax and coconut oil or just plain old spit. If the patch is loose fitting it will be all torn up and edges burned a little. This is with Pyrodex powder. Plastic wads on the base of bullets does not get melted nor do the shot cups in a shotgun. I would think plastic would melt before lead. A good test would be to get the pot of lead hot but not to melt stage and place a plastic wad onto the "hard" hot lead. Did it melt?? I bet it did. Now another test would be to get the lead just to melt stage in the pot. Place a lead bullet base into the lead and pull it out quickly. Did it melt? Now do it with a powder coated bullet. Hold them with pliers. Who is up for the test. There is no lead melting on the base in my mind. It is the escaping gases around the bullet causing the issues in my opinion.