With the M1 and M14, "out of battery" is when the bolt's locking lugs are twisted counterclockwise any amount off their rotating stops on a chambered round and the op rod's all the way forward against its stops.
"In battery" for the US military has always meant all the weapon's parts are in their normal safe firing positions.
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master