For a 9mm
a 124gr FMJ @ 1100fps drop from 25m zero to 100m is 12.4"
A 115gr @ 1200fps DROPS 10.8" below a 25m zero at 100m.
If a group center is 1 in high or low at 25 yds,it will be 4 in highER or lowER at 100 yds.
Fixed that for ya!
See right there is the problem. Using a 9mm 115gr @1200fps a group centered 1" high at 25y will be ~4" low at 100 most still hitting a 12" plate
No, sorry, you missed the mark. I think I know what you meant to say, but the drop involved with that 9mm load is about 11 inches, NOT 4 inches @ 100m. From a 25m zero.
If your group is centered 1" high at 25, and you aim for the middle of the 12" plate at 100, YOU WILL HIT DIRT. IF you aim for the TOP EDGE of the plate, you will hit the BOTTOM of the plate.
If your group is 1" LOW at 25, and you aim for the middle of the 12" plate at 100, you will hit dirt. If you aim for the top edge of the plate, you will most likely hit dirt or the very bottom edge of the plate. 11" (10.8") drop plus 1" low group center =12" (11.8") so by aiming at the top of the 12" plate and having almost exactly 12" of drop, (combined drop plus 1" low group center) your rounds will land at or very close to the bottom edge of the plate.
If I'm shooting far with a handgun,its not so good to hold the whole blade and part of the slide above the rear sight.Its not repeatable.
I disagree. Holding up the front sight, and as much extra as needed is the method I use, it works well for me, and is repeatable, although some guns make it easier than others.
For example, my favorite long range pistol is my Ruger Blackhawk .45Colt 7.5" barrel. (its my favorite not because its the best for long range, but because its FUN) I know exactly how much front sight to hold up to ring the TWO HUNDRED yard gong on the rifle range. And, its repeatable, because the "sweet spot" is right where the front sight blade goes vertical.
One example of a gun that wasn't easily repeatable was a Browning HighPower that a friend had me try. I had to hold up to a point about an inch and a half back on the slide to get on target at 200 yds. BUT, the only reason it wasn't easily repeatable was because there was no reference mark.
Putting a mark on the gun (paint, tape, etc) would have made it easily repeatable. Elmer Keith had some custom sights made for some of his long range shooting, with inlaid gold bars at different spots on the sight blade, for reference marks. It works.
The method of simply aiming enough above the target to compensate for the drop ALSO works. BUT, usually this hides the target from the view of the shooter.
I hold up the front sight with the target perched on top of the post. In my younger days, when I could balance a dime on the front sight (and it
stayed there, till the hammer fell) and the eyes of an eagle, ringing the 200yd gong (and offhand, to boot) was almost easy. Of course, 30+ years of practice with that one gun, one load, and at that distance might have had something to do with it...
Now that age has taken a toll, I have the eyes of a rhino, and the steadiness of a calm Chihuahua, so its not quite so easy as it used to be, but I can still do it once in a while.
And, I can still do it with any gun you hand me, allowing for a few ranging shots...