@II__SUSHI__II didn't work for me. i've just went on upgrading my sturmgewehr 1-5 (the rank 20 assault wep) and it didn't bump up the damage counter at all. getting the feeling that it's only tracking my sidearm damage since i did some form of damage with it once in a while
Man! wouldn't it be nice to have an reproducable/easy to fix/workaround issue for a change! Sorry to hear you do not get it working. My best guess is you should try some of the other assault weapons and see if any of these do the trick.