^^ Thank you for the info. This was ammo bought at the range I went to. I never buy range ammo at a range store, but didn't have time to buy the usually ammo I buy in 9mm from another gun shop. They carry the same ammo in .40 also. I never have problems with their 9mm.
I believe it is some lead residue after all, first time I've seen it for multiple guns. Currently only own Rem Oil, but used that this afternoon and scrubbed with bronze brush. A tad bit did come off, but I had to scrub pretty hard in both directions. Really hoping I didn't damage the barrel in...