The purpose of the log book would/could show that a person is serious about their training and attaining the skills necessary to carry/use their firearm with the utmost care and responsibility. Not just getting or doing the "minimum" to satisfy the requirements to get your CCW permit. It shows that you have gone above and beyond to get the most training and practice that you possibly can, and that you are more than capable in using your firearm to defend yourself or loved ones.
After you have been in a shooting and shot your attacker, then you don't need training records to show that you are more than capable in using your firearm to defend yourself or loved ones because you already demonstrated this aspect. If you are in court, it isn't because of your training, but because there is some question as to the legality of your shoot and all the training in the world won't change whether or not your shoot was legal.
This very issue has been brought up in court many many times, wether it involved a police officer or a civilian. The question would be asked, "what qualifications do you have that shows that you are trained and capable of carrying this firearm ? "
Baloney. First of all, if you are on trial, your lawyer isn't going to want you on the stand. Secondly, your qualifications to carry, if you are in a CCW/CHL state are indicated by your license....but this won't be an issue if you are qualified to carry, but if you were justified in your shooting. Again, your quals won't change the shooting.
Since when do you have to be "qualified" with a substantiated paper trail to defend your own life?
I would much rather be able to show that I have gone above and beyond the minimum requirements, because it was "that" important to me, and I took it "that" serious, rather than "just" having the basics. Keep in mind that this is just my opinion, although I am glad to see that somone who I feel is very qualified (Mas Ayoob )also shares the same opinion.
While citing the hearsay appeal to authority you learned from this thread is great and all, explain how the records will affect the circumstance of a shooting.
If you are in court, there is something potentially wrong with the shooting such that the issue has gotten you to court. Hopefully it will be resolved in your favor, but I don't see how shooting records will resolve the issue. Are you sure those same records won't show how you, as a well trained firearms carrier, should have known better than to pull the trigger when you did? After all, with so much training, you should have been a better shot, known the law better, waited a little longer instead of shooting so soon, etc.