Hi I a have been offered a Mauser Oberndorf in 9x57 that is in a non original condition, it has been drilled, it has a diffrent safety and bolt handle, and the stock is changed. Does the action becomes weakened when it has been drilled? My plan is to restore it and change the barrel and calibre to 8x57JS but i am a bit concered regarding the higher pressure of 8x57 compared to the 9x57,can the action handle the higher pressure of modern 8x57 loads even if it has been drilled?
If this "drilling" means just holes for scope mounts it doesn´t weaken the action. The pressure difference between 8x57 and 9x57 isn´t too big. And because yours rifle isn´t in original condition, those holes do not even lower it´s value according to price.