firing pin
Dear Sir:
Relax - this is simple.
Put the firing pin into the metal ring in the stock (or on a har block), grab hold of the rear flange with the safety verticle and press down hard! The flange assembly will move down the firing pin. As it is far enough down you will be able to rotate the very rear end of the firing pin and remove it - the flange will come clear off and you can replace the spring (I hope you're using a WOLF spring).
Harry B.