Every time a gun is fired, a shell casing is left behind. Mayor Michael Bloomberg traveled to Albany on Tuesday to push a bill to put traceable codes on each of those shells. He came back empty-handed.

Bloomberg and gun control advocates want to require manufacturers to stamp shell casings with microscopic codes, so detectives can trace them back to the owner. The bill was pulled from the State Senate floor, when three upstate Democratic Senators opposed it. By pulling the bill before it was formally voted down, lawmakers may re-introduce it later in the legislative session.

Brooklyn Republican Marty Golden, usually a Bloomberg ally and a former police officer, says he might have crossed party lines to vote for the gun control measure. But he feels this bill is flawed.

“We’d like to see the date [the law takes effect] extended so that the technology has time to be better perfected,” Golden says.

The loss suggests yet another problem for Democrats in the senate's narrow majority: many of them don't support the usual liberal agenda. They're from conservative districts that until recently sent Republicans to Albany.

Golden says imposing longer jail terms for illegal gun use has been an effective deterrent.