I don't have an 'old' bolt action, but I'd venture to think the sear/trigger engagement needs a tiny adjustment (make the trigger a touch Heavier) ?? The sear isn't completely releasing the firing pin when headspace is expanded with a chambered round. Did the rifle work before or is this a 'new' rifle? If worked b4, what changed ? Have you taken the bolt apart and cleaned ? A rifle that age may have dried up grease inside the bolt/firing pin channel.
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