The conversation over coffee started off well enough.

Around 8 a.m. on Friday, Representative Ralph Norman was holding court inside a diner in Rock Hill, S.C., where he would spend the next hour hearing from constituents.

Struck by the red T-shirts worn by members of an advocacy group, Mr. Norman started by talking about guns, a discussion the group wanted to have.

Mr. Norman, a Republican, has faced heavy criticism for what happened shortly after.

At some point, the lawmaker reached into his blazer pocket, pulled out his gun and put it on a table in what he later said was an attempt to show that firearms themselves are not dangerous.

In a statement on Saturday, Mr. Norman, who has a concealed-weapon permit, defended his action, saying that what he did was not dangerous.