For those who did not say, were you mentored, or did you stumble through the learning curve on your own? In my case, I had outside influences help me learn. My father was not a reloader. He was good at many things, but wasn't mechanically inclined.
Learned on my own referencing and reading load manuals. Reading magazines was useful. Eventually years later bought a Pro Crono that caused me to realize that book loads/velocity listed were not necessarily what could be achieved in a rifle with a generous chamber and bore. I also started measuring for concentricity (bullet alignment). It has been a science project since then, learning from testing.
