I have a pre 64 win model94 there is no spring tension on the hammer when in the fired postion, should there be? very little at the half cock postion and plenty at the full cock, is this correct? I am going to shot it to see if it has enough power to fire it tomarrow. If I need to replace the mainspring how do I do it? also need to replace the rear sight, do I just punch it out of the dove tail?