The National Firearms Act of 1934 created a registry for fully automatic firearms. The registry was closed to civilian individuals by the Firearm Owners Protection Act of 1986, meaning all lawful machine guns had to be registered by May 1986 and any machine guns manufactured after that date could only owned by special excemption. The law in question has no registration requirement, unlike Illinois recent assault weapon registry and sales ban.

Registered machine guns have only been used in crimes 4 times since 1934 and two of those were unlawful police use during the commission of a crime and one was military with his service rifle. There are over 638,000 civilian registered machine gun in the US.

Unlawful machine guns are used in crimes more often in recent years. The recent prevalence of “Glock switches”, which illegally convert a Glock handgun into a machine gun, has increased machine guns being used in shootings. There are other means to convert various firearms to fire fully automatic, some as simple as a bent coathanger or 3D printed parts. The exact number of illegal or converted machines guns being used or recovered is not well documented, but detection of events of automatic fire in cities with acoustic shot detection increased from around 400 in 2019 to 5,600 in 2021. The ATF recovered more than 1,500 conversion devices in 2021. That trend has increased.

The law does not stop criminals and it does not address gun deaths in any meaningful way. Mental healthcare reform and improving socioeconomic circumstances would reduce gun deaths by up to 2/3 by reducing suicides using a firearm. Using a magic wand to remove semi-automatic rifles would reduce gun deaths by <2%, because that is how often they are used to kill. Under 9,000 people are murdered with a firearm every year, ~43,000 die in car accidents(~14k alcohol involved), ~80-100,000 from overdoses, and 480,000 die from smoking related illness.