Some observers argue that the discrepancy between what the larger public wants and what gun control measures are really passed in to law by Congress is due, at least in part, to effective gun rights lobbying. One aspect is the sum individual politicians get from gun rights groups, for example in from of campaign contributions, which according to campaign finance law have to be reported to the Federal Elections Commission (FEC).
Drawing on FEC data The Center for Responsive Politics
has published an extensive list of members of congress and the amount of money they received in contributions. The list is headed by incumbent speaker of the House of Representatives, Paul Ryan, has so far received most funds attributed to gun rights lobbying. All members of Congress in the top ten are members of the Republican party and most are serving in the Senate.
The same source also notes that President Donald Trump has been on the receiving end of gun rights money to the tune of $970k compared to his former Democratic rival for the presidency, Hillary Clinton, who raked in some $1.1 million from pro-gun control groups.