Police say Gregory Rodriguez was shot and killed by Wayne Bengston in Montana after Bengston found Rodriguez with his wife.
Reports say after Bengston killed Rodriguez he beat his wife with a pistol and then drove away before killing himself.
Rifleman's Journal followed Rodriguez on hunting trips around the world and showed spectacular film from those trips.
Rodriguez also founded Global Adventure Outfitters, a supply store for outdoorsmen and was an editor at Shooting Times Magazine.
Police say the woman worked for a gun manufacturer and they don't think Rodriguez and the woman were having an affair.
The police chief said "It's pretty much an open-and-closed case, homicide and suicide."