My expectation would be very low chances of return to zero.
Most of them Field mounts were not at all high precision or well engineered. Perhaps as mentioned they had a better class for actual sniper rifles, but most of the ones on farmers' 303s were not made for high precision remove and replace operations.
And sadly, the gunsmiths that mounted them were VERY variable too. They didn't have Tek screws then, but boy there were some doozies.