The Florida law, which took effect last October, was the first, The New York Times reports. Under that law, a prostitute who grabbed a client's gun and killed him has not been charged and apparently is in no danger of prosecution.
Like the Florida law, most of the new statutes do away with the duty to retreat and allow the use of deadly force as long as someone is intruding in a house or car, the Times said.
The National Rifle Association has been lobbying for the laws and plans to expand its effort to more states.
"If they make a decision to save their lives in the split second they are being attacked, the law is on their side," Wayne LaPierre, executive director of the NRA, said. "Good people make good decisions. That's why they're good people. If you're going to empower someone, empower the crime victim."