On Wednesday, just hours before he went on the stage for the second GOP presidential debate, he found a way to combine the two into an event with plenty of political gun powder.

Surrounded by California supporters and sporting sunglasses, a sweatshirt and jeans, Mr. Paul fired 10 shots from a semiautomatic rifle into a box filled with the voluminous federal tax code. Each shot cleanly hit its target.

“I am a real conservative. I’m one who believes in getting rid of the tax code, having a single rate for everyone that reduce the burden for all of the public and makes government smaller,” he said in explaining the purpose for the event.

Just hours later, Mr. Paul was called first by CNN debate moderator Jake Tapper to introduce himself to a national televised audience.