Maj. Christopher Lunney, a former member of the provincial reconstruction team in Kandahar, is charged with three counts of negligent performance of a military duty and two counts of breach of duty.
Cpl. Joshua Baker of Edmonton was killed in the training range accident in February 2010.
Last June, Maj. Darryl Watts and Warrant Officer Paul Ravensdale were charged with manslaughter in the incident.
They were also each charged with four counts of unlawfully causing bodily harm and one count of negligent performance of a military duty.
Baker was killed during a routine exercise at a shooting range about four kilometres from Kandahar.
The Canadian Forces National Investigation Service alleges that proper safety procedures were not followed during the exercise.
The investigation continued after the initial charges were laid, culminating in the charges against Lunney.
"These charges reflect the seriousness with which the Canadian Forces regard weapons safety," said Lt.-Col. Robert Delaney, commander of the investigation service.