Gunsmithing is like music, engineering, machining, etc. You can keep learning for ever.
How to learn can have to do with your learning style.
Learning styles - Wikipedia, the free encyclopedia
Some people learn in a class room, some from a book, some by doing it, some by watching it, some by listening, etc.
20 years ago I started going to pawn shops and dickering them down on their prices for broken guns.
Then I would take the gun apart, clean it, oil, it and decide what spare parts to buy from Numerich gun parts corp.
Firearm Parts & Accessories | Military Surplus | Numrich Gun Parts
When the gun was fixed, i would sell it on consignment at another pawn shop.
I am not saying that is fastest way to learn, but it was all fun and paid me $1/hour.
I do not think gunsmithing is a good way to make money.
There are some incredibly good gunsmiths that if they had called themselves engineers, would have made 4 or 5 times as much money.
There are some real crooked gunsmiths that make good money, but they would have made 10X as much if they called themselves investment counselors.