Some semiautomatic rifles popular with veterans and sportsmen — but also carried by the alleged Aurora, Colo., movie-theater shooter and the Beltway snipers — could remain legal in Maryland under significant changes being weighed to the assault-weapons ban championed by Gov. Martin O’Malley.

The Democratic governor’s gun-control legislation, which, among other provisions, would require potential gun buyers to submit to fingerprinting and training, passed the state Senate last month. But it is bogged down in a powerful committee of the House of Delegates, according to several committee members and other legislators.

The House Judiciary Committee has struggled to reach agreement on the definition of an assault weapon, members said. Lawmakers said they could vote as soon as Wednesday to alter that part of the bill, which would gut a key provision of O’Malley’s attempts to curb gun violence in the wake of the Newtown, Conn., school shooting.

Members are considering removing features common to many semiautomatic rifles modeled after military ones, potentially leaving such guns as the Colt AR-15 and its many copycats legal for purchase. Such weapons are used in only a small fraction of Maryland homicides but have become a symbol of gun-control efforts nationally.

“I believe the AR-15 is out,” said Del. Luiz R.S. Simmons (D-Montgomery), a committee member. “The committee has done a lot of work talking to both sides to try to figure out what are the features of the gun — not focused on the name like AK-whatever — but certain features that should be banned.”

Senate Democrats are preparing to consider several proposals that aim to limit gun violence, but a controversial ban on hundreds of weapons and parts is unlikely.

The stall in the Maryland House came as the push for a new federal assault-weapons ban faltered in Congress, where Senate Majority Leader Harry M. Reid (D-Nev.) said Tuesday that he would introduce gun legislation without an assault-weapons ban written by Sen. Dianne Feinstein (D-Calif.).

In Maryland, disagreements on O’Malley’s bill were always expected between the House and Senate on mental-health provisions. But with the potential growing for a chasm on assault weapons, members of O’Malley’s staff and leadership of both houses have begun girding for the possibility that the final weeks of the session could include a fight over the assault-weapons provision.

O’Malley spokeswoman Takirra Winfield said Tuesday that the governor still very much wants a full assault-weapons ban as part of the plan.

“The governor proposed a very comprehensive bill that is overwhelmingly supported by Marylanders, and that was . . . passed by the Senate,” Winfield said. “The governor is committed to working with the members of the House to make sure the safest and most comprehensive approach prevails.”

Del. Kathleen M. Dumais (D-Montgomery), vice chairwoman of the House Judiciary Committee, is one of several from O’Malley’s party who have grown skeptical that a full ban is needed.

Dumais said that after 10 years in Annapolis hearing gun-control bills, she’s more accepting that there are rural parts of Maryland where gun ownership is a central part of life.

She said she was also swayed in part by the testimony of some of the more than 1,300 people who traveled to Annapolis this month to oppose the bill before her committee. Dozens, including some Olympic hopefuls, testified that their livelihoods in competitive shooting could be threatened. Many veterans said they viewed it as a right to own weapons like the ones they were trained to use.

“Several people who testified about the competitive shooting gave me pause as to whether a complete ban is appropriate,” she said.

Vincent DeMarco, president of the grass-roots group Marylanders to Prevent Gun Violence, countered that there’s nothing “symbolic” about an assault-weapons ban.

“The guns that killed so many people in the Aurora movie house, that wounded congressman [Gabrielle] Giffords, these weapons need to banned,” DeMarco said.

Speaker Michael E. Busch (D-Anne Arundel) may be O’Malley’s best hope for holding the assault-weapons ban together in the House. He assigned the governor’s bill to two committees and has remained circumspect about how the two will vote to send the bill to the full House, meaning he could maneuver to override a majority of the Judiciary Committee.

In an interview, Busch cited a cafeteria shooting last year at a high school north of Baltimore as evidence of the need for an assault-weapons ban.

“Look, there’s no doubt every American, every Marylander, has the right to defend their home,” Busch said. “But the question here is: What’s the practical use of these types of weapons . . . especially when in a criminal assault their firepower becomes extraordinarily destructive?”