I have been loading Rem 150 gr flat pionts. Today at the range a guy was shooting his 45 auto with Lazer Cast slugs and was telling me they don't lead his barrel. I was thinking of getting some of these for my Marlin 30/30. I understand that with lead you can't push them as fast as say a jacketed bullet. How hard can these be pushed? What do you guy's load these to? The price is hard to beat.