Forty-eight Republican Senators sent a strongly worded letter Thursday to Attorney General Merrick Garland and ATF’s acting director, warning them that the ATF needed to withdraw its proposed rule affecting pistol braces for ARs and other commonly used sporting rifles.

In the letter, the Senators warned that the ATF’s propose rule change would turn millions of Americans into criminals overnight.

The ATF and the Biden/Harris Administration want any firearm equipped with a pistol brace to be regulated by the National Firearms Act, which currently regulates machineguns, short-barreled weapons, suppressors and other weapons.

“This is plain wrong,” the Senators wrote in their letter. “The proposed rule is worse than merely abdicating your responsibility to protect Americans from criminals; you’re threatening to turn law-abiding Americans into criminals by imposing the largest executive branch-initiated gun registration and confiscation program in American history. We urge you to turn back. Correct this mistake and withdraw the proposed rule.”

Earlier this month, more than 140 lawmakers from the house sent a similar letter to the Biden/Harris administration.