Type your answer here ...The revolver barrel gave me a very hard time too. As it turns out, it's not marked accurately on your map (several diaries/scavenger missions suffer from this). Although it's in the same general area as the other parts, it's not where it appears to be (the map marker points you to the roof of one of the little buildings, right?). If you drive directly to the marker (no need to jump to the roof) and look back the way you came, you'll notice a rusty fence. On the other side of the fence is the body of a beat-up old car without a hood. The Revolver Barrel is inside the hollow where the hood/engine of that car would be.