What is the difference between 30-30, 30-06 and 308?

I want to know the differences in rifling and size. When you buy to reload a pack of bullets just says 30 cal.By looking into a 308 and 3006 and 3030 barrel could the difference be seen?I just don't have all three to compare. I am getting into the physics behind this stuff...

I am really into this rifling "stuff" Really cool stuff.