Many pro-gun Senate Democrats, including several from conservative states, said that Congress should take up gun legislation in the new year. Senators have already said they will propose laws to ban large clips of ammunition and high-capacity magazines. But in order to pass, those laws would need the support of some senators who have high N.R.A. ratings.

The House has not considered gun control legislation since 2008, so some members have not had the opportunity to vote on the issue. But more than half of the members of the 113th Congress, which begins in January, have been given an “A” rating by the N.R.A., and a large number of those would have to support new legislation in order for it to pass.

Rep. John A. Yarmuth of Kentucky said he had been largely silent on gun violence, but was now “as sorry for that as I am for what happened to the families who lost so much in this most recent, but sadly not isolated, tragedy.”

Senator Patrick J. Leahy of Vermont, the chairman of the Judiciary Committee, said that his committee would hold hearings next year “to help in the search for understanding and answers.”

Senator Joe Manchin III of West Virginia, a strong advocate of gun rights in the past, said “everything should be on the table” as gun control is debated in the coming weeks and months.

Notes: Ratings are for the 113th Congress, which begins in January. The latest available ratings are used. The N.R.A. gives an AQ rating, which is equivalent to an A, when it uses a questionnaire in lieu of a voting record. Campaign contributions are for the 2012 election cycle for members of the House of Representatives and the 2008, 2010 and 2012 cycles for members of the Senate, and include money from the N.R.A. given to the candidate and to his/her affiliated leadership committee.