I just got a new B&C stock for my Zastava M70. The B&C model is Mauser/Interarms X (#2197-97), I was told that it is the closest fit to Zastava M70 rifle. Everything fits well except on opening the bolt to full extent the bottom of the cocking piece rubs against the comb of stock. Any idea what could be done to rectify it, as sanding will spoil the finish & the shape of the comb. THANKS