Mayors Against Illegal Guns Tries Campaign Tactic

WASHINGTON -- The anti-gun violence group launched by New York Mayor Michael Bloomberg is rolling out a vote-scoring system for gun bills that's similar to the score-keeping of many conservative campaign groups, including the National Rifle Association.

Bloomberg and co-founding Boston Mayor Thomas Menino announced the plan to members of Congress in a letter sent Tuesday, saying they would grade lawmakers based on votes on background checks, assault weapons, high-capacity magazines and gun trafficking, among other issues.

"For too long, the only voice that has been loud enough to influence Congress has been the Washington gun lobby's -- that's how we've ended up with ineffective gun laws that have fueled our country's gun violence epidemic," said Bloomberg in a statement.

"Now we're working to make sure that the voices of the more than 900 bipartisan mayors in our coalition -- and the 90 percent of Americans who support commonsense reforms like background checks for all gun sales -- are heard loud and clear," he added. "It's time for Congress to take action to save lives and protect our communities."

The announcement comes as the Senate takes up a gun violence measure that more than a dozen Republicans have pledged to filibuster. It also comes as the conservative Heritage Foundation has made opposition to the gun measures a "key vote" on its scorecard.

The mayors also released a new ad, aimed at Washington, D.C., and swing states, that features Neil Heslin, the father of slain Newtown, Conn., student Jesse Lewis. Heslin testified earlier this year in favor of the Senate gun bill.

WATCH the ad below: