Light Primer Strike Issue
I recently picked up a non firing H&K HK4 with one mag. Looked it over and performed the pencil test, which it failed. Everything else seemed to be in order so figured it was firing pin related. Bought it, took it home, and disassembled. I found that the firing pin had broken, but everything else looked good. I ordered a new firing pin and another mag (never can have too many, right?) from Numrich. I got the new FP and installed it. I put a spent casing with marker over the primer into the chamber and test functioned it. The FP hit the spent primer, scratching off marker. I then inserted a cartridge and had a failed to fire. I tap racked, and had another fail to fire. I inspected the primers, and they had been hit, although it was too light to detonate the primer.
Looking at the schematic (found on Numrich website), it appears that the mainspring in the handle causes the force on the hammer to push the firing pin into the primer. After firing, the firing pin spring pushes the firing pin rearward to keep it in place with the hammer and everything ready for the next shot.
If this is true, the light primer strike should be caused be one of two things: 1) weak mainspring or 2) I got an "out of spec" firing pin.
I am not all that experienced with pistol repairs, so I would like to get some advice, input and guidance from those that are and how I should proceed. Thanks for the help.
