We try to diligently observe the basic four rules of gun safety when handling our guns. One rule, the one to keep your trigger finger clear of the trigger guard, doesn’t mention where that finger should be when not in the guard.
Now, I’m not a gun instructor (hope to be someday soon), but the index finger position in the photo seems very natural to me. Putting the index finger along the longitudinal axis of the gun keeps it out of the guard while keeping it in position to fire when ready.
Some arguments have been made that, if the trigger finger is properly indexed, it is permissible to ‘muzzle’ suspects, bystanders and fellow officers/shooters. I couldn’t disagree more.
Here’s an excerpt from a November, 2002 article from the Police Policy Studies Council:
Recently, a respected firearms instructor for a major agency wrote a piece advancing the premise that as long as good habits are displayed concerning “indexing” the trigger finger, in what we at PPSC call “register” position, it was permissible to allow your muzzle to cover suspects, suspected innocents and other officers.
I agree with the other instructor about the importance of proper trigger finger indexing, but disagree strongly with his dismissal of muzzle control as a component to practical firearms safety. We need both.
The special operations units that disregard muzzle control as a cultivated part of organizational culture have records of accidentally shooting themselves and each other. I know of an FBI HRT member that shot himself in the thigh with his 1911 while manipulating it at home. SAS members will admit, in relaxed social settings, that they have shot each other in both training and operational environments. Without a culture of muzzle control, along with trigger finger control, it is just a matter of time until we shoot ourselves or an associate. [more]
Emphasis mine. I’m sure that these concepts apply equally to civilian shooters as well as occupational shooters.