"You have clubs out here that get together to have AR-15 building parties — that’s how easy it is to find parts these days," Winkler said. "You no longer have to be an ironsmith to put these guns together."
Build parties are about completing 80% lowers. Fitting the rest of the parts has never needed much in the way of skill or tools.
BATF, though, recently issued a ruling limiting the ability of individuals to share, borrow, or rent tools, so the build parties have pretty much dried up.
So, of course, people are making jigs that allow you to complete an 80% upper with inexpensive hand tools.
Held, any person (including any corporation or other legal entity) engaged in the business of performing machining, molding, casting, forging, printing (additive manufacturing) or other manufacturing process to create a firearm frame or receiver, or to make a frame or receiver suitable for use as part of a “weapon … which will or is designed to or may readily be converted to expel a projectile by the action of an explosive,” i.e., a “firearm,” must be licensed as a manufacturer under the GCA; identify (mark) any such firearm; and maintain required manufacturer’s records.
Held further, a business (including an association or society) may not avoid the manufacturing license, marking, and recordkeeping requirements of the GCA by allowing persons to perform manufacturing processes on blanks or incomplete firearms (including frames or receivers) using machinery, tools, or equipment under its dominion and control where that business controls access to, and use of, such machinery, tools, or equipment.