The California Legislature passed SB 704 on Tuesday, which would require background checks on the purchase of industrially manufactured firearm barrels—essential to complete unserialized, untraceable 3D-printed ghost guns. Firearm barrels are the only parts of a functional firearm that cannot effectively be produced using a 3D printer. Currently, these barrels are unregulated and can be purchased online or in-store without a background check or any restrictions. SB 704 is the first measure of its kind in the U.S.
