On June 7, 2021, the ATF published the unofficial version of its upcoming proposed rule 2021R-08, Factoring Criteria for Firearms with Attached "Stabilizing Braces". This rule would institute a scoring system for pistols with stabilizing braces and other features to determine if the firearm is a "short-barreled rifle" (SBR) rather than a pistol and therefore regulated under the National Firearms Act (NFA), which requires the owner to register and pay tax stamps for each SBR.
Im4Rights has updated its Fight the ATF resource page (https://www.im4rights.com/fight-atf) with the latest information, and we will continue to update as more information becomes available.
"The Second Protects the Rest!" --Tom