The Wagoner County Sheriff's Office said the homeowner and his adult son were in the home when three males wearing masks and gloves tried to break in at about 12:30 p.m. The homeowner's son shot the intruders with a rifle, deputies said, killing all three.
So they were armed, masked, and did this in broad daylight; sounds like they were planning or just willing to hurt anyone they found inside. Barring something else turning up in the investigation, I doubt the rifleman has to worry about charges.
Added: this story says an AR-15. Y'know, one of those EBRs we're told are useless for self-defense.