Any mauser and it's variants need the barrel shank bedded for an inch or two in front of the recoil lug. Since the front action screw goes into the recoil lug, there is a tendency for that to become a fulcrum of sorts when you tighten the screw down and also compresses the wood (unless you sleeve the hole).
My guess is the bedding is an attempt to free float the barrel. Over time I bet the thickness of the stock at the recoil lug 'compressed' and allowed the barrel to set lower into channel. Or there was some wood removed from the action area and made the barrel set too low.
Several past threads on bedding mausers and I think MD did a magazine article about it.
