You’d be surprised then - first of all, no “hammer-forging” is required, nor is 7075 whatever.
Take this for example (warning, language!) https://www.northeastshooters.com/xen/threads/diy-shovel-ak-...
Take this for example (warning, language!) https://www.northeastshooters.com/xen/threads/diy-shovel-ak-...
That guy is building a receiver, then assembling. Most people who are into it are just assembling.