The Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) has announced its intention to ban the manufacture and sale of a popular type of ammunition used in AR-15 rifles.

On Feb. 13, the ATF issued a notice of its intention to reclassify the M855 round, also known as "green tip" 5.56, as "armor-piercing ammunition" and, therefore, illegal under the Gun Control Act of 1968 and Law Enforcement Officers Protection Act of 1986. The laws ban handgun ammunition that contains certain materials. Rounds designed to be fired from rifles, such as the "green tip" 5.56, have been exempt from these laws for decades.

The ATF has decided the availability of AR-15 variants it classifies as pistols means the "green tip" 5.56 is now handgun ammunition. It used the same justification to ban the importation of 7N6 5.45×39, a round often used in AK-47 style rifles, in April of last year.

The "green tip" variant of 5.56 is one of the most widely available types of ammunition. Shooting enthusiasts and hunters prefer the round in long-distance situations.

News of the banishment of the popular round sparked backlash.

Gun rights groups slammed the ATF and asked its members to contact the agency to voice their opposition to the proposed regulation change during the public comment period.

"Commonly available ‘green tip' M855 and SS109 rifle ammunition that is primarily intended and regularly used for ‘sporting purposes,' like target shooting, has been exempt from federal law banning armor-piercing ammunition for decades," the National Shooting Sports Foundation told its members in an action alert. "There is no question that the steel-tip, lead core 5.56 ball ammo has been in wide use by law abiding American citizens for sporting purposes."

"They are claiming that this ban is needed to protect the police," Virginia Citizens Defense League president Philip Van Cleave told the group's members in an email. "A total fabrication. I've not heard of a single officer being harmed by M855."

The National Rifle Association's Institute for Legislative Action (NRA-ILA) sent in a message to its members in regard to the change, saying, "In a move clearly intended by the Obama administration to suppress the acquisition, ownership, and use of AR-15s and other .223 caliber general purpose rifles, the Bureau of Alcohol, Tobacco, Firearms, and Explosives unexpectedly announced today that it intends to ban commonplace M855 ball ammunition as ‘armor piercing ammunition. The decision continues Obama’s use of his executive authority to impose gun control restrictions and bypass Congress."

The ATF's new restriction marks the third time in 2015 the agency has moved to implement stricter gun control.

"It isn’t even the third week of February, and the BATFE has already taken three major executive actions on gun control," the NRA-ILA said in the same message. "First, it was a major change to what activities constitute regulated ‘manufacturing' of firearms. Next, BATFE reversed a less-than-year-old position on firing a shouldered ‘pistol.'"

"Now, BATFE has released a ‘Framework for Determining Whether Certain Projectiles are ‘Primarily Intended for Sporting Purposes’ Within the Meaning of 18 U.S.C. 921(a)(17)©,' which would eliminate M855’s exemption to the armor-piercing ammunition prohibition and make future exemptions nearly impossible."

The public comment period on the proposed regulation change will end March 16, 2015.