"Fifty-six votes, a majority of the Senate believes we ought to have one sane policy" on gun rights on federal lands, Coburn said.
Sen. Barbara Boxer, D-Calif., said allowing more guns onto Corps property would increase danger to the dams, flood control systems and other crucial water projects.
"This critical infrastructure is a target for terrorists," she said. Allowing more guns "sets up a national security threat. It endangers people."
Army Corps lands are used for recreation by 370 million people annually, more than visit the property of any other federal agency. About 80 percent of them are within 50 miles of urban areas, making them accessible destinations.
Also Wednesday, the House Veterans Affairs Committee voted by voice to require a judge or magistrate to declare a veteran is dangerous before the person's name is entered in the background check system's database of people barred from getting firearms.
Currently, the Veterans Affairs Department sends the system the names of veterans it has declared unable to manage their financial affairs - 127,000 names since 1998.
Supporters of the measure said veterans who can't handle their money aren't necessarily dangerous.
"It's arbitrary. It's inconsistent and it's unreasonable," Rep. Jeff Miller, R-Fla., chairman of the committee, said of the current process.
The veterans department opposes the measure, saying veterans in the database already have the ability to appeal.