In 2007, the sponsor of "encoded ammunition" legislation in Maryland urged lawmakers across the country to introduce the same kind of legislation in their states. The bill would require ammunition manufacturers to engrave a serial number on "the base of the bullet and the inside of the cartridge casing of each round" of ammunition for popular sporting caliber center-fire rifles, all center-fire pistols, all .22 rimfire rifles and pistols, and all 12 gauge shotguns.