Stocks of other gun companies fell, and one sporting-goods chain said it would temporarily stop sales of military-style firearms. In Washington, some former opponents of gun control signaled that they may change their position, potentially giving stricter gun laws their best chance of passage in years.
The most notable rejection of the gun industry came when the private-equity firm Cerberus Capital Management announced it would sell the maker of the rifle used in the massacre, which it called a "watershed event."
The shooting "raised the national debate on gun control to an unprecedented level," Cerberus said in a news release. "We are investors, not statesmen or policy makers."
In an acknowledgment of the changing political climate, the National Rifle Association promised "to offer meaningful contributions to help make sure this never happens again." It scheduled a Friday news conference.
Bushmaster, Remington and DPMS are among the brands made by Freedom Group Inc., the largest firearms maker in the U.S.
The Madison, N.C., company sold 1.1 million rifles and shotguns last year, along with 2 billion rounds of ammunition. Its customers include law enforcement and military agencies, as well as retailers who serve hunters and gun enthusiasts.
Cerberus, a large private-equity firm best known for investing in Chrysler and other troubled corporations, appeared to have been under pressure from two sources: investors and the threat of more gun control.
Officials at California's huge teacher pension fund said they were reviewing a $600 million investment in Cerberus in light of the Connecticut shooting. Through its stake in Cerberus, the California State Teachers' Retirement System owns a 2.4 percent stake in Freedom Group.
Pension fund spokesman Michael Sicilia confirmed the fund owns about $4 million in shares of Sturm Ruger & Co. and $1.7 million in Smith and Wesson.
Cerberus filed papers in 2009 to take Freedom Group public, but it withdrew the bid in 2011 without saying why. A Cerberus spokesman declined to comment Tuesday beyond the company's statement.
Freedom Group has lost money in four of the last five years, according to financial filings on its website. Revenue in 2011 was $775 million, down from $848.7 million in 2009. Slightly more than half of its 2011 revenue came from guns, much of the rest from ammunition.
The assault weapons ban that expired in 2004 restricted the sale of some types of guns like those made by Bushmaster. The adoption of a similar law "could have a material adverse effect on our business," Freedom Group said in a statement.
In 2010, Freedom Group said it would close its Bushmaster plant in Windham, Maine, and shift the work to a plant in Ilion, N.Y. At the time, New York Sen. Charles Schumer praised the move as a way to strengthen Remington's ability to compete for Defense Department gun contracts.
Firms like Cerberus are basically privately run pools of money that invest in companies on behalf of pension funds. On Tuesday, the fund attempted to distance itself from the national debate.
"It is not our role to take positions, or attempt to shape or influence the gun control policy debate," the firm said. "That is the job of our federal and state legislators."
Meanwhile, Dick's Sporting Goods Inc. suspended sales of all "modern sporting rifles," the industry term for military-style guns. The company also removed all guns from display at its store closest to Newtown.
Dick's has not promoted military-style guns as much as some other retailers. Its circular distributed in newspapers on Sunday had a full page of hunting rifles, but no military-style ones.
Wal-Mart Stores Inc., which offers Bushmaster rifles in some stores, said it would not change the guns it sells, but company spokesman David Tovar said the web listing for the Bushmaster "was taken down in light of the tragic events."
All the talk about additional gun control appeared to be driving increased gun sales, though. The Colorado Bureau of Investigation said it received a record 4,154 requests for background checks on Saturday, the day after the shooting.
That was slightly more than on its normal biggest day, Black Friday.
Bob Irwin, CEO of The Gun Store in Las Vegas, said customer traffic has jumped since the school shooting, with many customers concerned that more gun laws will be enacted. He has not pulled any guns from the shelf.
"My belief is the individual nutcase did this," he said. "The company that manufactured the gun didn't. That seems silly to deprive my normal customers of product because somebody misused a product from the same company."
Irwin agreed that the Connecticut attack demanded some kind of action. He suggested adding more security officers at schools.
Shares in publicly traded gun makers declined for a third-straight day.
Shares of Sturm, Ruger & Co. dropped 7.7 percent to close at $40.60. They have fallen almost 11 percent since Thursday, the day before the shooting. Shares of Smith & Wesson Holding Corp. fell 10 percent to $7.79 -- down almost 15 percent from their Thursday close.
Outdoor goods retailer Cabela's Inc. fell almost 6 percent to close at $38.77.