Since 1996, the National Rifle Association has invested about $395,000 to influence elections in Connecticut, the state that is home to the nation's latest mass shooting tragedy. Data downloaded from Sunlight's Influence Explorer show that the nation's premier gun rights lobby has given both to federal and state candidates.

Though the NRA has not had good success in Connecticut's congressional contests, at least 15 sitting members of the state legislature received contributions from the NRA. During the most recent session of the Connecticut state legislature, some 40 pieces of legislation were introduced involving firearms, according to records retrieved by Sunlight's Open States project. Among these were a bill to loosen restrictions on those qualified to purchase assault weapons and two that would have tightened gun control laws. None of them became law.  

MORE: A complete list of NRA campaign contributions in Connecticut races.

The state of Connecticut permits carrying handguns without registration.

Since 2010, the NRA has reported spending $8,000 on lobbying at the state, records from the Office of State Ethics show, although the National Sports Shooting Foundation, another gun rights group, has invested more than $20,000 in the past year lobbying Nutmeg State lawmakers on on firearms related issues. On the federal level, the NRA has spent more than $2.2 million on lobbying on issues from firearms, right to bear arms and on homeland security issues.

MORE: For data on the gun debate, see the Sunlight Foundation's resource page.

In the 2012 elections the NRA's super PAC spent more than $16 million on electioneering ads with most of the money opposing Democrats running for Congress. But despite their largesse, their return on investment in the 2012 elections was a low 0.83%.

At the other side of the firearms debate are groups such as the Mayors Against Illegal Guns and Brady Campaign to Prevent Gun Violence, groups that have a much lower profile than the NRA and less money to spend.

(Contributing: Anupama Narayanswamy, James Turk, Louis Serino, Jake Harper, Lindsay Young and Kat Lucero)