As young survivors of the Parkland shooting lead efforts to tighten limits on firearms, they have met deep resistance from strong supporters of gun rights, and both sides have dug in. But the renewed national gun debate — reignited again after the shooting in the Nashville Waffle House — has gotten the attention of a subset of people who are often overlooked: gun control supporters who own guns.

Many of these gun owners will never take part in marches or make public speeches. But interviews with two dozen gun owners around the country found what polls have shown — that many of them are firm supporters of some gun control measures. In recent weeks, some have grown more vocal, holding signs at demonstrations, lobbying lawmakers or writing letters to the editor, adding their voices to those of the protesting students.

Of the 60 million to 70 million Americans who own guns, measuring how many are likely to take part in activism in favor of gun control or to change their political choices over the issue is difficult. One rough proxy for those who do not want tougher gun laws could be the five million gun owners the National Rifle Association claims as members, said Robert Spitzer, the chairman of the political science department at the State University of New York at Cortland, who has written extensively about gun policy and politics.

The N.R.A. is staunchly opposed to new gun control measures, and events following the Parkland shooting may have deepened the resolve of its supporters. In March, according to filings with the Federal Election Commission, the N.R.A. Political Victory Fund raised $2.35 million — the highest monthly amount raised for the fund in records dating back to 2003, according to an analysis by the news outlet McClatchy and verified by The New York Times. The N.R.A. did not respond to requests for comment for this story.

Only a small number of gun owners seem to be stepping forward in activism in favor of stricter gun laws, and not all agree about which laws should be toughened. But advocacy groups that support increased gun control say they sense a new kind of participation in more subtle ways, such as calls from gun owners wanting to know what the groups do, and a greater willingness to listen. The shift could also have political implications: Some gun owners said they are now paying closer attention to which political candidates receive money from the N.R.A., which takes a hard line against firearm limits.

