A proposal to ban a bullet that can pierce armor has upset the gun industry and its supporters.
The bullet in question is the M855 "green tip," which is used in the popular AR-15 assault rifles.
Handgun bullets made of steel have been banned from public use since 1968. But the M855 has managed to avoid the ban because it is used in assault rifles, which aren't technically handguns, and fall under the category of sporting rifles used by target shooters and hunters.
The bullet would be banned under a new framework that was proposed earlier this month by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). The proposal is not finalized yet and is seeking public comment.
"No action has (yet) been taken," said a Justice Department spokesman.
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The National Rifle Association blasted the proposal as a backdoor attempt by the White House to impose new restrictions on gun owners.
"The Obama Administration was unable to ban America's most popular sporting rifle through the legislative process, so now it's trying to ban commonly owned and used ammunition through regulation," said NRA director Chris Cox.
AR-15 is the most popular firearm sold in America today. A semiautomatic weapon, it commonly known as an assault rifle, a description that gun supporters do not like.
There are other bullets that can be used with the AR-15 that are not included in the ban. They're made of lead and copper and are widely available.
It was also the weapon used in two of the most widely followed mass shootings -- in the elementary school in Newtown and in a Colorado theater.
Obama called on Congress to renew a ban on assault rifles following the Newtown shooting in 2013. But the effort ran into fierce opposition from the NRA, conservative lawmakers and some Democrats.
The NRA has already started gathering signatures for a letter to the ATF director B. Todd Jones and is asking its members to write their local member of Congress.
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"The NRA and our tens of millions of supporters across the country will fight to stop President Obama's latest attack on our Second Amendment freedoms," said Cox.
Gun safety advocates say the M855 is a threat to law enforcement officers since it can penetrate bullet-proof vests and can be used in certain types of handguns, the most common firearm used in violent crime.
"This is not a gun grab," said Brian Malte of the Brady Campaign to Prevent Gun Violence. "It's a proposed rule change to protect the lives and safety of law enforcement officers."
