I know there are a few of you guys that REALLY know your stuff. Do you do this for a living? Supplemental income? Hobby (it costs money)? If a guy (me) was wanting to get into doing some of this, what are the ESSENTIALS to learn? Books that would come in handy? I assume an apprenticeship wouldn't be a bad idea? I can really see myself getting into working on firearms. I just want to know what I would be getting myself into and what would be the best methods. I don't want to waste my time. THANKS, in advance!!!