I have these...
The Gunsmithing Course, the Milling Course and Lathe, Building the Ultimate 1911, Making Glocks Rock and all the Armorers Courses..most of their main materials.
They weren't even available when I started building rifles and pistols, like several decades, so when they came into my possession they were only of mild interest to me, but I like watching shows on the history of firearms too so I checked them out.
My review would be that the material is reliable and good.
It might not be close to in depth hands-on training from a reputable school, or an apprenticeship working with a Master Gunsmith, but there is nothing in these courses that I recall that is incorrect.
I've been building and working on guns for decades, but if a person doesn't know anything about this stuff one has to start somewhere.
At the very least... one can make the effort to watch a dvd before hacking up their 1911 or whatever gun they might have...why not?
It's better than some advice I see that gets thrown around.
