(Radio Iowa) – Iowa Attorney General Brenna Bird has joined a lawsuit that challenges a Biden Administration rule requiring registration of gun accessories known as pistol braces. Pistol braces were first marketed in 2012 as a way to help people with a disability stabilize a pistol by attaching it to their forearm, but people also use the device to brace a gun against their shoulder.

The Biden Administration has classified that configuration as a short-barreled rifle. It means pistol brace owners have to register the device and pay a 200 dollar registration fee. Iowa Attorney General Brenna Bird says since pistol braces have been legal for a decade, millions of Americans who bought one legally will become a felon if they don’t know about the new rule and fail to register the device by May 31st.

Iowa is joining two dozen other Republican-led states and the National Rifle Association in suing to try to block the Biden Administration policy on pistol braces. The rule is part of executive actions President Biden announced in early 2021 in response to mass shootings. The gunman who killed 10 people in a Colorado grocery store in 2019 used a pistol brace. The device was also used by a man who killed nine and wounded 17 others at a bar in Ohio in 2019.