First of all, don't think that any old load you throw down the pipe of the M83 will be a one holer. If you want to verify the accy of the fiber optic front, squre notch rear, you need to shoot a load that has been proven accurate in your gun.
Second, everybody is different! Selecting a sight system that works for you is a trial and error process. Nobody can tell you what will work for you. I'm 62, and my eyes (and nerves) aren't what they used to be -- 20 years ago, that group Fowler posted above was a gimme, today it would be posted on the "braggin wall". I just don't see "black on black" that well anymore except under perfect light conditions. I have three of Ken's front sights and recommend them highly if you can see them well -- I don't, except under perfect light conditions with help from reading glasses.
I've tried red dots, and for me, they just magnify the wobble -- 98 % of my shooting is off hand. From solid support, they are superior with my aging eyes, but for now, I think a handgun should have iron sights.
I like the FA Fiber Optic front sights w/square notch rear although, I have trouble picking up the rear in poor light situations -- I can see the front well enough to make a hit out to 50 yds off hand during legal shooting light. I also know that depending upon light conditions (time of day, time of year (location of sun on horizon)) point of impact does change.
Here are some groups with the FA Fiber Optic Front, Square Notch Rear
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FWIW,
Paul