Gov. Martin O'Malley waits to speak to advocates of stricter gun control laws at a March 1 rally at the Maryland State House. (Patrick Smith/Getty Images)

Maryland Gov. Martin O’Malley notched a victory late Friday in a House committee that had become a linchpin in his efforts to pass one of the most far-reaching legislative responses to last year’s deadly school shooting in Newtown, Conn.

After more than eight hours of debate, every major provisions of the governor’s gun-control bill, including an assault weapons ban and licensing and fingerprinting of gun buyers survived. Conservative Democrats had in recent weeks wavered on the governor’s assault weapons ban, but a core Democratic majority fiercely defended the bill against repeated challenges.

The rare joint voting session of the House Judiciary Committee and the chamber’s Health and Government Operations Committee, which share jurisdiction over the bill, was at times met with heckles and boos by hundreds of gun-rights advocates who crowded into the House office building down the street from the State House.

The crowd sighed as O’Malley’s proposed fingerprinting requirement narrowly passed an early vote. Three African American Democrats representing Baltimore City and a conservative one from Western Maryland joined Republicans in opposition to the measure.

“Why do the authorities need to retain the fingerprints,” asked Del. Nathaniel T. Oaks (D-Baltimore), who voted against the requirement, saying it would forever put the fingerprints of law-abiding gun owners alongside those of criminals in state and federal databases.

The most heated moment of the hearing came nearly five hours later when Republicans said the focus should be on criminals, not gun-owners, and appeared to win a vote to add a new law tightening prison sentences for those convicted of gun crimes. Several minutes later, House Judiciary Chairman Joseph F. Vallario (D-Prince George’s) announced that a Democrat had changed his vote and the measure, in fact, would fail. It was a nearly identical scenario to one that played out last month on the state Senate floor.

Shouts of “shame on you,” “communists,” and “we’ll remember in ’14,” rang out from the crowd and dozens stood up and left the hearing in protest. “That’s not democracy; that’s tyranny,” chimed Del. Michael D. Smigiel Sr. (R-Cecil), the author of the provision.

Republicans did win several small changes to the bill, including one spelling out that firearms that now exist in the state but that would be banned for sale as assault weapons could be willed to others.

They also won small changes protecting antique gun collectors and firearms dealers. Those in the voluntary Maryland Defense Force would also be exempt from some provisions of the governor’s new licensing requirement.

Del. Luiz R. S. Simmons (D-Montgomery) also narrowly won a change to the governor’s bill that will prevent those convicted of violent crimes but later able to get their records expunged from purchasing guns.

He failed, however, to roll back another change his colleagues advanced that would allow Marylanders to continue to purchase guns deemed assault weapons after the bill takes effect on Oct. 1, 2013, so long as purchasers show proof the sale began before October.

“I thought the purpose of the assault ban was to ban them,” Simmons said. “We’re going to flood the state with assault weapons and then declare victory on Oct. 1 … Maryland will be armed to the teeth by the time the bill takes effect.”

Vincent DeMarco, president of Marylanders to Prevent Gun Violence, nonetheless said the House had succeeded in making the governor’s bill stronger. He pointed to Simmons’s amendment, and another that will require gun owners to report lost or stolen firearms within 72 hours.

Shannon Alford, a National Rifle Association lobbyist in Maryland called the evolving bill a “fundamental infringement” of Marylanders Second Amendment rights.

The most significant changes to O’Malley’s bill were contained in a set of 10 changes agreed to in principle by committee members in private meetings on Thursday night.

Those changes stripped out nearly all restrictions on current gun owners in Maryland. But most notably, did not attempt to rewrite O’Malley’s proposed assault weapons ban.

Disagreement over the ban had left the gun-control bill languishing for over a month in the House, with even some key Democrats saying an all-out ban seemed unneeded given how rarely the weapons are used in Maryland killings.

The committee changes also removed any requirement that Marylanders who currently own a gun complete training to obtain a license to buy another one in the future.

Another amendment also would prohibit the state from seeking to force residents who currently own weapons that would be classified as assault weapons from having to register those guns with the state.

Owners of some 60,000 semi-automatic weapons in Maryland would have had to have registered their weapons before next year or have faced criminal penalties, including possible jail time, under the original version of O’Malley’s bill.

The bill is now likely to dominate House floor debate in the final full week of the General Assembly.