Simply put a 33% increase in sight radius provides slightly more visual reference of sight misalignment. It comes down to basic geometry.
Lets use 9" sight radius and 33% less 6". Plug those numbers into Brownells Sight Correction calculator. In a perfect world: At 25 yards a 1" error with 9" sight radius is the result of a 0.010" sight misalignment. That same 1" error at 25 yards with a 6" sight radius would be a 0.007" sight misalignment.
Which sight radius and sight misalignment do you think would be easier for the eye to perceive?
https://www.brownells.com/aspx/learn...aspx?lid=13093
Nobody has mentioned the fundamental optics issue yet.
When the sights are farther apart, if you have a crisp focus on the front sight, the rear sight will be farther from the plane of focus, and thus more blurry. This may offset some or all of the precision gained by the increased resolution in slide angle for a given misalignment of the sights, or it may lead to an increase in time to obtain a satisfactory sight picture.
I suspect that within the range of sight radii typically available on typical pistols, shooting at speed, it's probably a wash, and other factors are more important.
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Not another dime.
I personally shoot a little better with a G34 or G35 than I do with a G17 or G19.
The increased sight radius probably has something to do with that. I also like the way the longer gun balances.
From the viewpoint of the shooter, the front/rear sight picture of a shorter sight radius and wider front post might be difficult to distinguish from a longer sight radius and a narrower front post.
That is not to say that they are the same.
A longer sight radius given more "mechanical" advantage with respective.
A narrower front sight might be faster to acquire, but a wider front sight may be easier to precisely center - given time to do so.
Are you now, or have you ever been a member of the Doodie Project?
I believe @JohnO is referring only to how a longer slide can theoretically deviate "more" from center in terms of sighting than a shorter slide and still result in the same POI given the angle of deviation increases the closer you, or in this case the sight/muzzle, move towards the target.
Your point regarding sight dimensions and the effect this has on the shooter's perception and management of said dimensions, is connected to his point, but still subtly different.