This is actually my point. It didn't say "no one" is doing it. Even though his means are very crude, he still needs a furnace, a welder, and a lot of other to

This is actually my point. It didn't say "no one" is doing it. Even though his means are very crude, he still needs a furnace, a welder, and a lot of other tooling (receiver jig, etc.) to get to the point where he can use a bucket of pre-fab parts (most notably the barrel). That guy is building a receiver, then assembling. Most people who are into it are just assembling.