An additional 55 to 63 people have been murdered each year in Missouri following the state’s 2007 repeal of its permit-to-purchase (PTP) handgun law, which required all handgun purchasers to obtain a license verifying that they have passed a background check.

A California lawmaker proposed legislation Monday to make background checks and gun registrations requirements for anyone who builds plastic firearms, dubbed “ghost guns,” on a 3-D printer at home. The bill, by state Sen. Kevin de Leon (D-Los Angeles), would also apply to anyone who buys parts that can be assembled into a gun, Fox News reports.

2013 was Colorado’s busiest gun-buying year on record, partially due to legislation that now requires background checks for private firearm transfers, The Denver Post reports.

After hitting an all-time high in December, background checks for gun purchases have declined by nearly half.