Three home invaders dressed all in black and wearing masks and gloves probably thought they’d easily overpower the owner of a Broken Arrow (OK) home.

They clearly didn’t count on the homeowner’s adult son being there, armed with one of the best home defense firearms ever designed, an AR-15.

Three would-be robbers were shot and killed Monday when an Oklahoma homeowner’s son opened fire on them with an AR-15, authorities said.

Wagoner County sheriff’s deputies were called to the home in Broken Arrow, southeast of Tulsa at around 12:30 p.m. local time. When they arrived, they found the three dead suspects and two uninjured residents.

Sheriff’s spokesman Deputy Nick Mahoney said the suspects enetered the home through a glass back door with the intent to burglarize it. It was not immediately clear why they picked that home.

Mahoney said the suspects encountered the homeowner’s 19-year-old son, who opened fire after an exchange of words. Two of the suspects died in the home’s kitchen while a third was found in the driveway.

It was not immediately clear whether the suspects were armed, but Mahoney said the preliminary investigation indicated the shootings were in self-defense. The homeowner’s son volunteered to give a statement at the sheriff’s office.

A forth suspect, believed to have been the wheelman for the three deceased home invaders, has since been arrested.

BA homeowner shoots and kills three intruders. @KTULNews pic.twitter.com/XBtsr9mZ8a

— Burt Mummolo (@MummoloNews) March 27, 2017

19-year-old Americans armed with variations of Eugene Stoner’s rifle have been killing bad guys  since 1964.

The most common AR-15 configurations we see on today’s civilian market, featuring collapsible stocks, 16″ barrels, and standard capacity 30-round magazines, give homeowners a light recoiling, very controllable and precise semi-automatic rifle. The very common 55-grain M193 round FMJ “ball” round fragments in both tissue and in building matters at home defense distances.  Hollowpoint rounds designed for varmint hunting, law enforcement, and home defense, such as Winchester PDX1 “Defender” line can be even more devastating to bad guys, while breaking up faster when encountering build materials.

AR-15’s are more powerful and carry more rounds than handguns, while their bullets run the same or less risk of over-penetration and creating downrange injuries as most handgun rounds. AR-15s are far less punishing to shoot than shotguns loaded with quality defensive ammunition, and get back on target faster for follow-up shots if needed.

Commonly paired with a red-dot optic and a weapon light, AR-15s excel at battling bad guys both day and night, and are easily controlled by shooters of nearly any size or stature.

“America’s rifle” was used to save two lives in Oklahoma today, and enabled a single teenager to quickly triumph over three criminals.