I have used these two powders in multiple rifles and one of the differences I have noted (besides RL 26 being faster) is that I get copper build-up with RL 26 and zero copper with H1000 when using the same Berger bullets in each gun. The reason this strikes me as odd is that RL 26 claims to have a proprietary anti-coppering additive, while H1000 makes no such claim as far as I can tell. Has anyone else ever noticed this?