schematics for a 12mm pistol, aka schematics for a 12mm pistol, pistol, 12mm, and schematic

This delightfully colorful pamphlet shows you how to craft your own Hammerhead ballistic dispatch mechanism, or "gun" as they are sometimes called. All the instructions required are right here at your fingertips. An exceedingly clever logo depicts a brawny humanoid with a head shaped like... you guessed it... a hammer.

It tells you how to make a Hammerhead 12mm automatic pistol with the following components:
1 - brick of quick-mold plastic
1 - firearm trigger assembly
1 - firearm breech assembly
1 - firing pin assembly
1 - ammunition magazine assembly
2 - short steel pipes
1 - firearm sight assembly
2 - small springs
4 - handfuls of brass fittings
1 - bundle of brass pins
2 - steel pipe caps

Making this would take expertise in craft and expertise in pistols.
It weighs about 100 grams. It is a gun schematic. You're pretty sure it's worth about $16,000 on the open market.