When I talked to Mr Lee many years ago he said that he and Dean Grenell spent many days casting, testing,reloading and shooting on the Lee Property.
Yes with that background he did know a bunch.
Now if you REALLY want to read stuff by know it alls go to evil bay and find a copy of Herters catalog from around the late 60s then get one of their reloaders manuals.
There you will find many stories by 2 brothers that were so proud of themselves there wasn't a shirt made that would cover their necks,sleeves and have enough material left to go around their over inflated chests and button closed.