While I still experience that sensation of time slowing when I fire a flint lock, that time gives one the sensation of watching the hammer fall and the flash from the pan rolling over the barrel and the sound of the flint scraping along the frizzen. All of that sensation takes my attention away from the focus on the front sight and the target. When my full concentration is on the front sight and the steady pull of the trigger, all I am conscious of the sudden obscuring of the target by white smoke. I may sort of know that the fan went off, but that is a secondary experience.
So, let's do as
@Coinneach advises us, concentrate on the front sight only. Be one with the firearm as we pull the trigger.