Loaded Chamber: Training on how to avoid ND?

[ATLDave]

Step 1: Decide to unload the pistol.
Step 2: Unload the pistol (pulling the trigger is not part of unloading). Get all ammo and loaded magazines far away.
Step 3: Check your work on Step 2. Look into the magwell. Look into the chamber. Cycle the slide several times (if little shiny yellow or silver things are still coming out, go back to Step 2).
Step 4: Check your work on Step 3. Be sure enough that you'd bet your life on the pistol being empty.
Step 5: If you must pull the trigger or "hammer down, show clear," point the gun in a safe direction (not an interior wall, not at the ceiling on the first floor of a 2-story house, not at the floor in an apartment). When you're ready to pull the trigger, get paranoid and check Steps 2, 3, and 4 all over again. Pull trigger.

 

[Hoganbeg]

Several things:

Pulling the trigger is not a good way of verifying an empty chamber and should never be used as part of the unloading process; for just that reason. In fact, there are only three exceptions that I can think of: firing, dry-firing, and on some pistols, to allow disassembly.

Your friend needs proper training from a credentialed trainer.
If he has had such training, he needs to ask himself , "What procedures did I violate?" He then needs to ask, "Why did I knowingly violate them?" Over-confidence? Brain not engaged? He then needs to commit himself to doing it correctly every single time.

I have noticed the recent popularity on YouTube of demonstrating an empty chamber by racking the slide multiple times. As has been noted by others above, this proves nothing other than that the operator is lacking in knowledge. I mention this because as a species we learn a great many of our behaviors though the process of monkey see, monkey do. Mostly these things are absorbed uncritically without examination. There can also be an element of peer acceptance involved. The point is that bad habits that we are constantly exposed to can creep insidiously into our own use unconsciously and we must be constantly on guard against them.