Sorry, what is a flash sight picture?
Flash Sight Picture means you see a quick snap-shot of the sights.
Exactly.
Terminology / verbage can often be confusing. Many different words are used to describe the same things.
Another term for "flash sight picture" is IMPERFECT sight picture. "Imperfect" refers not only to a standard sight picture with the front sight post centered in the rear sight aperture, but also to any "alternative" sighting technique that you are using, be it focusing solely on the front sight, to being somewhat off center of mass with a dot scope, or whatever.
When you are trying to make a compromise between speed and accuracy, as practical shooters and assaulters do, your aimpoint on the target becomes larger, as does your window of opportunity for landing a hit.
Take an IDPA target for example. The "sweet spot" on the target is a circle roughly 8" in diameter to be engaged from around 25m and closer. In the IDPA competition world, your goal is to maintain your rounds within that 8" circle, while firing as fast as you can.
Now lets look at say a slow aimed fire bullseye target. The sweet spot is approx 6" or so at 1oo meters, and your goal is to maintain your round within that smaller space at a greater distance. Sight alignment becomes very critical.
For the IDPA target, your sight alignment is NOT nearly as critical as is for the bull target. Fundamental errors that you may make are magnified with RANGE, hence, fundamental errors that result in a 3" POI change at 25 meters are compounded to a 12" POI change at 100 meters. You have MUCH more leeway up close, which is good for both the "game" and the real world.
Knowing this, a smart "practical" shooter should strive for identifying their OWN compromise between speed and accuracy, and once known, the shooter works on improving speed, while maintaining that "sweet spot" in accuracy.
Flash / imperfect sight pictures are part of that equation.
By identifying how "sloppy" you can be with the sights at a given range, you begin to identify how fast you can pull the trigger and still hit your intended area. I know that in order to hit that 8" circle that I DONT have to have perfect sight alignment up close, and I DON'T have to have a perfect center mass hold in the circle, I can be "close" and still achieve my goal. As soon as I see the sight return in the AREA I can break off another shot and be confident that I hit in the AREA that I want to hit. The speed in which the sight returns to that area after recoil is where the word "flash" comes into play. As that sight "flashes" back into the intended area, that "flashed" image should register in my brain and tell me that I can break off another shot.
This "flash" sight picture applies with all manner of sights in any type of quick aimed fire.
I read a term that sums it up pretty well on the Brian Enos forum. It goes "learn to see what you NEED to see...".
That's perfect. What that means is that the SHOOTER must learn what they NEED to see in order to achieve a hit on various sized targets at various ranges based on THEIR own ability. An excellent shooter who applies the fundamentals well, may obtain that hit without opting for a center of mass point of aim. Where as a "challenged" shooter such as myself, with sloppy fundamentals (trigger pull = ASS) may very well need to pick up a point of aim much closer to center of mass in order to make up for poor fundamentals. It all depends on the shooter.
Training is key. Natural ability helps, and so does good equipment.
