As the director of the Bureau of Alcohol, Tobacco, Firearms and Explosives prepares to defend his budget before angry pro-gun senators Thursday, the agency is hitting the brakes on a plan to ban a type of armor-piercing ammunition after pushback from gun activists, sources tell Gawker.

"ATF is basically being bullied and strong-armed into not enforcing the law," an official with knowledge of the deliberations tells Gawker.

The plan, part of a larger framework developed with industry leaders and law enforcement to standardize how the ATF defines illegal ammunition, would have removed a "sporting purposes" exemption from two types of "green-tip" armor-piercing .223-caliber ammo rounds, developed for military use and popular in assault-style weapons like the AR-15 rifle. (A 5.56mm version of the ammo in question can be seen making a clean hole through a quarter-inch of welding steel in the video above.)

ATF released its plan—developed with input from gun lobbyists and ammo producers—last month so the public could comment on it, and comment they did. Since then, pro-gun activists, led by lobby groups and politicians, have assailed the proposal as part of a larger conspiracy to deprive citizens of their firearm freedoms.

"Second Amendment rights require not only access to firearms but to bullets," 52 Republican senators wrote in a letter to ATF Director Todd Jones on Monday protesting the plan. "If law-abiding gun owners cannot obtain rifle ammunition, or face substantial difficulty in finding ammunition available and at reasonable prices because government entities are banning such ammunition, then the Second Amendment is at risk," the senators wrote.

Although the proposal was essentially a bureaucratic move by agents within the ATF, the House Judiciary Committee's chairman has rallied conservative colleagues against it by pinning it on Barack Obama. And Sen. Roger Wicker (R-Miss.) lumped the proposal in with an alleged White House "plan to chip away at Second Amendment rights."

Those responses, and veiled threats by members of Congress to jam up the ATF as it seeks approval for its 2016 budget, have reportedly led the agency to reconsider the plan:

The agency has officially said it will be gathering public comment on the proposal until next Monday, but this afternoon it abruptly changed course. "Although ATF endeavored to create a proposal that reflected a good faith interpretation of the law and balanced the interests of law enforcement, industry, and sportsmen, the vast majority of the comments received to date are critical of the framework, and include issues that deserve further study," the agency stated in a release published Tuesday. "Accordingly, ATF will not at this time seek to issue a final framework."

Sources inside the ATF expected the planned ammo ban to be a major bone of contention this Thursday, when Jones faces a Senate appropriations subcommittee led by conservative Sen. Richard Shelby (R-Ala.) "to review the Fiscal Year 2016 funding requests and budget justifications" for the agency.

The ATF framework itself is little-understood, and it has been the subject of intrigues and recriminations by gun lobbyists—some of whom actually helped the ATF develop the very framework they're protesting against today.

Even among opponents of the ban, there is no question that the M855 and SS109 steel-core rounds are capable of piercing body armor used by police officers; many high-powered rifle rounds can do that. But since passage of the bipartisan Law Enforcement Officers Protection Act of 1986, ammunition manufacturers have been able to seek legal exemptions for certain types of rounds "primarily intended to be used for sporting purposes."

As long as such ammo couldn't be used in pistols, it could still be bought and sold by hunters and sportsmen for rifle-shooting. "Congress expressly sought to protect law enforcement officers from the effects of a projectile that, although originally intended for a rifle, could be fired from a handgun," the ATF's plan states. "Congress recognized that the threat to officer safety generally corresponds to the type of firearm police officers are most likely to encounter on the streets."

The problem is, the very gun industry that sought a sporting exemption for M855 ammo now makes handguns to chamber the armor-piercing rounds—making for what what one manufacturer calls "an extremely versatile weapon platform":

"These AR-type handguns were not commercially available when the armor piercing ammunition exemption was granted in 1986," the ATF's stillborn plan stated, concluding that "to ensure consistency," its framework—again, developed in 2012 with input from gun industry leaders, lobbyists, and law enforcement—would require it to take away to "sporting" exemptions for "both the SS109 and M855 cartridges."

The problem has been worsened by the fact that while virtually no ammo makers had sought exemptions for 25 years, the ATF was suddenly flooded by at least 30 exemption requests since 2011—forcing the agency to come up with an objective standard to judge whether some armor-piercing rounds were worth keeping in circulation, and to inform manufacturers "so they could plan their business decisions," ATF spokeswoman Heather Colbrun told Gawker.

The impact of the proposed framework on sportsmen, the ATF says, would have been minimal: Owners could keep the rounds they already have. And 32 different manufacturers make 168 types of .223 ammunition that would have still been legal for sale, according to Colbrun, so there was no danger that law-abiding gun owners would have been disarmed.

More troublingly, many of the same groups and corporations that lambasted the ATF framework as creeping anti-gun socialism actually helped the agency draft that framework: "In November 2012, ATF held four meetings with interested parties representing law enforcement, the firearms and ammunition industries, and non-governmental organizations" to get their input on the framework, the ATF guidance stated. "We went out and talked to law enforcement, we talked to the industry," Colbrun said. "We were committed to a transparent process."

Gawker has obtained a list of the attendees, who included:

  • The NRA
  • The National Sport Shooting Foundation
  • Cutting Edge Bullets
  • Remington Arms
  • FGI Ammunition
  • Hornady Manufacturing
  • Winchester Ammunition
  • The Sporting Arms and Ammunition Manufacturers Institute
  • Committee for the Right to Keep and Bear Arms

The National Sports Shooting Foundation, which is based near the site of the 2012 Sandy Hook massacre, made no mention of its involvement in the ATF deliberations in a post on its site last month titled, simply, " Oppose ATF's 5.56 M855 Ball Ammunition Ban." Nor did the NRA mention its part in those talks when it sent alerts this month to members calling for them to protest the proposal:

In the meantime, rumors of a ban, stoked by the lobbyists, led gun-lovers to make a run on the ammunition, giving manufacturers a windfall. The steel rounds were flying off shelves as fast as they could be restocked, one Virginia gun-shop owner says: "We've purchased more of this in the last three weeks than we have in the past six months."