For this reason, we used the old FBI light technique almost exclusively (light held way out to one side with one hand, while the other hand held the weapon in front of you and prepared to fire on who/whatever was illuminated by the light). Some of us still got shot...
Yep, there was some thought that went into this technique originally, and it wasn't arrived at in some random manner. I wouldn't necessarily consider it obsolete, either.
I really, really dislike the idea of target identification with a weapon-mounted light when innocent parties may be present, as this violates a basic safety rule, so for such situations, I'd still prefer to rely on a hand-held light. Agree ...
Weapon mounted lights ... in a L/E, civilian environment, anyway ...
Remember when the little plastic gadgets were first being sold to attach a mini-maglight to the underlug of a revolver barrel? Yep, I tried one way back then ... very briefly.
Nowadays, with the improvements in technology continually occurring, these things are becoming more practical and useful, although I personally believe their usefulness is a bit more limited than some other folks. Of course, I don't have any vested interest in selling them, either.
I have reason to train with lights. I also use lights in my work. A lot. I have no less than 6 different handheld lights available in my car, and often carry 2-3 of the various smaller units on my person when entering/clearing structures. I've had to loan them to a partner, and I've had to borrow one from a partner. None of them are weapon mounted lights, though. It's not like I couldn't use one if I desired, since one of my previously issued service pistols was equipped with a rail, and my newest issued pistol is equipped with a rail. I simply choose not to carry/use one myself ... for the time being. These things can, and may, change.
I know other instructors who favor them, others who don't (majority, including a SWAT instructor/team member) ... and some who are simply ambivalent about weapon-mounted lights on handguns. Longarms are another story.
Wanna know what I really dislike? The thought of being illuminated by another cop's weapon mounted light, as he/she comes across me ... and the only light he/she has in a low light environment is the one on the business end of his/her weapon. Considering the elevated physiological and psychological states that may likely exist in folks facing potentially life threatening situations ... and the sometimes poor trigger finger control & safety issues I see exhibited even on a static range ... this causes me no small measure of concern when I may be on the other end of the weapon light.
Threat identification is vital. Crucial. The ability & importance to see and clearly identify a potential threat can't be understated. Ditto the area
behind the perceived threat.
I feel that weapon mounted lights have their place.
I feel that folks who elect to use them should carefully consider the various circumstances in which they would potentially be a benefit, as well as a potential liability.
I feel that training can be very useful in helping someone make a determination of which circumstances are which ...
I like that the improvements in the weapon mounted lights are also resulting in improvements in handheld lights, too.
I think experience, knowledge, training and anticipated/perceived threat conditions will influence someone's choice of weapon and/or handheld light source choices ... and that's probably as it should be.
Just like the muchly repeated old 'rules' of a gunfight ... rule one being 'have a gun' ... it could be said that the first 'rule' of being able to see in conditions of low light and darkness is ... have a light. The type of light can be variable, and the determination influenced by a lot of factors.
Weapon mounted lights mean that the muzzle of the weapon is also covering whatever is illuminated by the light ...
The hand needed to control and use a separate light source may mean one-handed shooting is necessary. This may adversely affect the potential shooting skills, accuracy and controllability needed by the shooter. Another one of those pesky training issues to which some users may not give as much consideration as we'd probably all prefer ...
I dislike having my trigger finger focus and concentration directed anywhere except whether or not to function the trigger. I'd rather retrain my some aspects of my grip, than start changing my trigger finger's function and control. This may affect choice and use of some weapon mounted lights.
Just some of my thoughts ...
This isn't exactly a black & white subject ... no pun intended.
For me, I prefer to consider the various circumstances and situations which I may face, and then work to maximize my advantages and reduce potential disadvantages and liabilities.