All American Western 108 (June/July 1949) offers up another excellent Johnny Thunder tale by Kanigher, Toth and Giacoia.
A villain named Silk Black leaves a silk handkerchief behind after a crime spree, containing a silver bullet. The bullet is engraved, announcing that Johnny Thunder will kill Sheriff Tane with it. Johnny is so upset by this that he almost lets it slip that the sheriff is his father. Incidentally, there have been very few scenes of Johnny as John Tane in the last few issues.
Silk Black and his gang then set up a variety of situations in which Johnny is almost tricked into shooting his father, and the climax of the tale plays this as well, as Silk Black holds the sheriff in front of him as a hostage. Johnny does not let his fear affect his aim, and he shoots Silk Black with the silver bullet.