The “boyfriend loophole” provision is “a refocus on should we be just looking at domestic partners or should we be looking more broadly at intimate partners?” he said.

Studies also show that domestic abusers with guns inflict a disproportionate amount of violence on their partners, and that the victims are overwhelmingly female. Abused women are five times more likely to be killed by their abuser if the abuser owns a firearm, according to the Giffords Law Center to Prevent Gun Violence, a gun safety group. Roughly three-quarters of all intimate partner murder victims were also victims of stalking by their partners, according to the National Center for Victims of Crime.

“The share of homicides committed by dating partners has been increasing for three decades,” said Shannon Watts, who founded Moms Demand Action for Gun Sense in America, a group that supports tighter gun laws, in response to the massacre at Sandy Hook Elementary School in Connecticut in 2012. “Women are now as likely to be killed by dating partners as by spouses with guns.”

The reauthorization bill has one Republican co-sponsor, Representative Brian Fitzpatrick of Pennsylvania. Representative Kevin McCarthy, the House Republican leader, is urging Congress to extend the expired law for the rest of the year to continue funding services to survivors at current levels. Ms. Baker, of the N.R.A., accused Democrats of “playing politics” with the bill by inserting the so-called boyfriend provision as a “poison pill” so that Democrats can portray Republicans who vote against it as anti-woman.

The N.R.A. has decided to “score” the vote on the Violence Against Women Act, meaning it will keep track and publish how lawmakers vote in an effort to either reward or defeat them in the next election. While the move is not likely to keep the bill from passing the House, it does make it more likely that the “boyfriend loophole” provision will be stripped from the act when the measure arrives in the Senate.

“Anybody who votes for this should take the outrage of the N.R.A. and wear it proudly,” said Representative Debbie Dingell, Democrat of Michigan, who drafted the provision as a separate bill and fought for it to be included in the Violence Against Women Act.

Ms. Dingell — whose husband, John D. Dingell Jr., who died this year, served on the N.R.A.’s board of directors — has spoken powerfully of her experiences as a child, cowering in the closet in fear of her father, who struggled with mental illness and had a gun.