You'd be surprised what a hoffman lower or FGC9_2.0 can take.

Gotta stop those guns made from kids. (Per the first image caption in the article).

A ghost gun is displayed before the start of an event about gun violence in the Rose Garden of the White House April 11, 2022 in Washington, DC. Biden announced a new firearm regulation aimed at reining in ghost guns, untraceable, unregulated weapons made from kids. Biden also announced Steve Dettelbach as his nominee to lead the Bureau of Alcohol, Tobacco, Firearms and Explosives

The New York Police Department has reportedly seen a 60% increase in ghost guns seized from city streets for the past two consecutive years. NYPD recently traced some online ghost gun sales to a “ghost gun printing operation” filled with 3D printers and firearms nestled within a daycare center.

I have no idea from this if the increase in ghost guns was attributable to 3D printing, or if the increase even represents a significant number.

It also seems like this would be really difficult to enforce. You can buy hardware or kits to build your own printer, or you can buy an old printer off someone else.

All that said, if it represents a reasonable concern and they figure out a way where it's not trivially circumvented (both of which seem unlikely), I really couldn't care less about a background check.

What are the requirements for other weapons? Does California require a criminal record check for firearms purchases too? I’m Canadian.