Washington, D.C.

With the terror-inspired attack in San Bernardino, Calif., following closely on the heels of mass shootings in Colorado Springs, Colo., and Roseburg, Ore., New York's Democratic U.S. senators continue to push uphill for gun legislation in Congress.

But in a quiet and under-the-radar way, it is the National Rifle Association and its allies that are making progress on their legislative agenda on Capitol Hill.

One example: Buried in the must-pass National Defense Authorization Act, signed into law by President Barack Obama the day before Thanksgiving, is language that prohibits the Environmental Protection Administration from regulating spent ammunition shells and shots as toxic substances under federal law.

"Prohibiting the EPA from banning traditional ammunition is a huge victory for hunters, recreational sportsmen and our military," the NRA said in its release. "This ensures that our military, hunters and sportsmen will have access to traditional ammunition at a reasonable cost."

In a news release, the National Shooting Sports Foundation, based in Newtown, Conn., just six miles from the site of the 2012 Sandy Hook Elementary School mass-shooting, hailed approval of "a top legislative priority." The law will preserve "our hunting and recreational shooting heritage" against encroachment by "radical anti-hunting organizations," NSSF said.

Passage of the ammunition measure may seem like yet another unremarkable trip through Washington's lawmaking sausage factory. But in reality it speaks volumes about the continued lobbying clout of the NRA and particularly the NSSF.

With mass shootings dominating the news at regular intervals, Sens. Charles E. Schumer and Kirsten Gillibrand have pursued legislation to expand background checks, prevent those on the terrorism watch list from buying guns, and impose stiff penalties for gun straw purchasing and trafficking.

They have called on the American people to "rise up" and overcome congressional inaction by sheer force of numbers.

But while it shuns major proposals such as background checks, Congress is willing to hand pro-gun allies small victories such as the one involving ammunition and the EPA. In that case, dominant Republicans were aided by a few rural "Red State" Democrats such as Sen. Jon Tester, D-Mont.

Since the Sandy Hook Elementary School tragedy on Dec. 14, 2012, the NSSF has expanded its presence on Capitol Hill to the point where its annual spending on lobbying now exceeds that of the much-larger and better-funded NRA.

And even though it's the lobbying against expanded background checks and other such measures that gets the headlines, the smaller (but still significant) items such as the EPA ammunition bill represent the bread and butter of gun lobbying.

NSSF represents 12,000 gun manufacturers, wholesalers, retailers, importers, publishers and shooting-range owners. The group says its mission is "to promote, protect and preserve hunting and the shooting sports."

The dispute underlying the ammo measure is unusual on a number of fronts. First, it pits the gun lobby not against its usual opponents — advocates of gun control such as the Brady Campaign to Prevent Gun Violence. Rather, it is environmental organizations who fought the NSSF and NRA over the environmentalists' contention that the main component of U.S. ammunition — lead — is hazardous to birds and wildlife who might ingest spent pellets.

Also, notwithstanding President Barack Obama's advocacy for expanded background checks and other gun-control measures, Obama's EPA also opposed the environmentalists in arguing that regulation of ammunition is beyond the agency's legal limits.

In New York, the SAFE Act's regimen of tough gun-control regulations remain highly unpopular with New York's hunting constituency, estimated at 700,000 by the state's Department of Environmental Conservation.

And although Gov. Andrew Cuomo was instrumental in winning legislative approval for the SAFE Act in the wake of the Newtown massacre, he has tried mightily not to alienate New York's hunters.

In 2013, he boasted about reducing in-state hunting license fees by 24 percent, noting that New York was fourth in the nation for hunter spending that generated $290 million in state and local taxes.

But it is unlikely he has made much in the way of inroads. "I choose not to comment on any of this right now," said Tom King, president of the New York State Rifle & Pistol Association.

Controversy over guns actually has proved to be a positive for the gun business. Gun manufacturing in the U.S. has more than doubled since 2008, according to data gathered by the Bureau of Alcohol, Tobacco, Firearms and Explosives.

Very few firearms companies publicly report revenues but those that do are seeing profits up in recent years. The largest rifle manufacturer in New York by far is Remington in Ilion, maker of the Bushmaster AR-15 variant used by Adam Lanza in the Newtown mass shooting in 2012.

The second largest is Just Right Carbines of Canandaigua, which makes a lightweight carbine rifle that shoots 9mm pistol ammunition.

In the pistol category, the largest in New York is Kimber Manufacturing in Yonkers, which features a replica of the original model 1911 .45-caliber pistol used by U.S. military forces in World Wars I and II.

On the EPA ammunition-regulation front, the pro-gun side scored a major legal victory a year ago when a three-judge panel for the U.S. Court of Appeals in Washington sided with the agency in resisting a petition from 101 environmental organizations to get the agency to regulate spent ammunition under the Toxic Substances Control Act.

Such regulation was necessary to "protect wildlife, human health and the environment against the unreasonable risk of injury from bullets and shot containing lead used in hunting and shooting sports," the environmental groups said. Among those species at risk were bald eagles and condors.

The NSSF countered that there was "simply no sound scientific evidence" that "traditional" ammunition is a hazard to wildlife.

The appeals court panel disagreed with the environmental groups, pointing to the law's specific exclusion of bullets and shot from the definition of "chemical substance" subject to EPA regulation.

Regulating spent ammunition would require EPA to regulate "cartridges and shells — precisely what (the Toxic Substances Control Act) prohibits," the panel wrote.

One of the environmental groups' lead lawyers, Bill Snape of the Center for Biological Diversity, insisted advocacy for controlling lead ammunition will continue.

"The NRA certainly did win a round in that battle, but the effort to regulate ammunition is not over," he said, insisting the groups' bid for EPA regulation was never about stopping hunters or limiting guns.

They want to see hunters switch to "green" ammunition made with copper or copper alloys, he said.