Maybe a first step would be the local library or yard sales. Lots of times they have older books on guns and shooting. You can gain lots of good info from past pros who are no longer with us, and save a lot of cash. That's how I gleaned a lot of knowledge back when I started (pre internet).
I got serious about 1980 and was finding books from the 1950's for pennies.
I wish I could remember some names, but that info is long gone from my febrile brain.
It's good to be the king.