Sites like DEFCAD or Odysee host the blueprints. Note that the State Department has previously fought to keep these files offline under export control laws (ITAR).
You generally won’t find 3D-printed guns for sale in a traditional store or online marketplace like eBay or Amazon. buy 3d printed gun
People often buy "parts kits" (barrels, triggers, slides) which are not legally firearms, and then print the "frame" or "receiver" themselves to house those parts. 4. Safety Risks Sites like DEFCAD or Odysee host the blueprints