There's your culprit (probably)! I can only go by my own experience fitting my A4 clone into a NOS Keystone C stock, It took several attempts and some vary careful bedding work to remove wood from the base.
As supplied (if yours is the same) the action sits too high in the woodwork, causing feeding and accuracy issues, plus some very unpleasant recoil characteristics.
Does the trigger feel uncomfortably high in the trigger guard?