Paul Doering, 49, managed to blast three people at a reenactment by the Dakota Wild Bunch, when for some reason his weapon contained live rounds instead the blanks they usually use.
Thankfully no one was fatally injured but the bullets did shatter a leg bone of Carrol Knutson, 65, hit the forearm and elbow of John Ellis, 48 and caused minor injuries to Jose Pruneda, 53.
Investigators have not made any comments on why the incident happened at the Hill City tourist town in North Dakota, or said whether they think the shootings were accidental.
Mark Salter, a U.S. Attorney's office spokesman said Doering did not enter a plea and that the indictment issued last week was sealed by the federal court.
But investigators earlier this month found that Doering had served more than five years in Minnesota prisons on multiple felony convictions.
South Dakota law says that a person convicted of a felony in South Dakota or another state cannot possess or have control of a firearm for 15 years, while federal law prevents felons convicted of crimes punishable by more than one year in prison from possessing any firearm or ammunition unless the person has had their civil rights restored by the state where they were convicted.