I have a Remington early production 760 in 30-06 and have located a 308 barrel for it -- what other components (besides the magazine) need to be changed out to make it a 308? Do the shorter cartridge versions have a shorter stroke, i.e. is the mag spacer at the front, so the stoke remains the same, or at the rear, allowing a shorter stoke, and if so what part shortens the stroke? I have ordered a headspace gauge set, so that will be properly checked.