The NRA tip above – keep a shooting diary – doesn’t mention the purpose of the exercise: CYA. If you’re ever involved in a defensive gun use (DGU), you could be subject to intense prosecutorial scrutiny. If they really want to nail you – a possibility that usually depends on the firearms-freedom friendliness of your particular location – your antagonists will sell you to the judge and/or jury as . . .
a trigger-happy gun nut. While some gun writers reckon that’s reason enough to curb your enthusiasm (e.g., not install a lighter trigger on your self-defense gun), there’s no harm in proactively assembling proof that you’re a well- [even if self-] trained gun owner. If push comes to ballistic shove and your DGU gets caught-up in an anti-gun jihad, a book detailing your training will help your defense. Who knows how much, but some.