@ 10:41 pm (GMT)
The factory setting should have been around 35 inch-lb. 25 is not quite secure enough and could invariably lead to the same stringing under high recoil. Or it would simply allow the screws to become looser in the field unless loctite is employed. It also allows more movement at the lug, would really bash it around.
In either case, once you feel this, you can be assured that the bottom plastic is coming to grief.
Check the bottom plastic and washer closely to see if there is any damage. If not, consider pillar bedding (or even just pillars in the manner shown in the Tikka bedding thread). If the bottom plastic is damaged, consider replacing with aftermarket alloy.
Very annoying, I really feel for you.