World’s First 3D Printed Metal Gun

[Beowulf]

How, exactly, would they be too expensive to make when you could literally just code the (already known) shape of the part into a computerized machine? I know the technical drawings may be unavailable these days, but it's not like you couldn't get a guy with a pair of calipers to measure all the relevant parameters.

CNC end mills tend to not be able to make cuts that slope in the Z direction. The two solutions are jigs that rotate to part so it's flat at the angle you want, or to have steps in the z profile. There's a video on Youtube with a guy talking about a conversion kit that changed a weapon from pan magazine feed to belt feed. The original manufacturing method had specialized horizontal mills that cut various profiles. Cheap for high production, but high start up cost. They want to make replicas, because originals are now scarce and expensive.