AN armed hold-up man had the tables turned on him when a store clerk drew his own weapon and threatened to blow his head off!

“I pulled my gun because I wasn’t going to allow anyone to take something that doesn’t belong to them,” the clerk, Iraq War veteran Jon Lewis Alexander, told The ENQUIRER.

After Alexander stuck his firearm in the punk’s face, the would-be thief backed out of the store – with Alexander’s gun aimed at him the whole time.

“One of the cops told me later, ‘You’re a lucky man. That guy could have killed you,’” Alexander, 54, recalled.

“I said, ‘No, I don’t think so. He’s actually the lucky one. I didn’t pull the trigger. He isn’t in the grave right now.’ ”

THE CREEP SURE DID GET LUCKY! Alexander served 30 years in the military, including four tours in Iraq, where he manned a 50-caliber machine gun atop a Humvee.

Back in the States, Alexander was working at Beer:30 in Marionville, Mo., on Sept. 1 when the thug walked in around 9 p.m. He was smoking a cigarette, and Alexander asked him to put it out.

“When he took the cigarette from his lips, I saw he was holding a gun down his side,” said Alexander, a married man who’s also been a prison guard and private investigator.

“He came up to the counter and told me, ‘You need to give me all your (bleeping) money.’

“I saw that he was about to raise his gun and point it at me. But before he could, I reached across the counter with my left hand and blocked his arm.”

Alexander – who says he carries a loaded Walther PPX 9 mm handgun in a holster on his right hip for protection – reached for his own firearm.

“After I stopped him from raising his gun, I drew my weapon and rested it on his bottom lip,” said Alexander.

“I leaned toward him and said, ‘You need to get out of here or I’ll blow your (bleeping) head off.’

“His eyes were glassy like he’d been drinking, or was on drugs, but he sure looked shocked. He didn’t say a word and slowly backed out of the store.

“I kept my weapon pointed at him to make sure he didn’t take a shot at me.”

After the man left, Alexander called 911. The police have yet to make an arrest, even though the store’s owners released surveillance footage of the drama.

Meanwhile, Alexander has been hailed as a hero.

“I’ve gotten a lot of positive feedback,” he said. “People have told me they wished there were more people like me to stop people like him. One woman said, ‘There are not many real men left. You’re one of them.’”