A Georgia man was fatally shot after debating the 21-foot rule, a self-defense tactic, investigators said.

>> Read more trending news

Richard Splichal, 34, and Spencer Warren, 29, were debating how close Splichal could get to Warren before Warren could fire his gun under conditions of the Tueller Drill, which says it takes 1.5 seconds for an attacker to cover 21 feet, the same amount of time it takes to draw and fire a weapon.

When Splichal came toward Warren, Warren fired his .357 revolver twice, striking Splichal once in the chest, WFXG reported.

Warren was arrested and charged with involuntary manslaughter and possession of a firearm during the commission of a crime, WFXG reported.