The bullet doesn't "rise" - it's falling as soon as it exits the barrel. It's the angular difference between the sight axis and the bore axis that, depending on the zero, makes the bullet cross the sight axis twice:
View attachment 24725
A word of caution -
The two zeros should be verified independently, as depending on factors such as barrel length, bullet weight (length), load, etc., that far zero can and will vary, sometimes drastically. What this means in the real-world is that we can only say that you're "zeroed" for
the distance at which we actually zero: everything else is a guess, until we pull down some data with actual rounds downrange.
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In terms of your new suppressor-height sights on your handgun,
@djalford1985 , you'll really want to get out there and check that initial POA/POI for yourself, and verify zero.
Night Fission's website only states that their standard sights will regulate to what the handgun manufacturer regulates to. For the XDm, for example, we see the following:
View attachment 24726
^ Image taken from XDMAN.com 's gracious hosting of the current and past XD Owners Manuals.
Note that the distance cited is 25 yards - but it doesn't mention bullet weight (length) or load specifics. This is because for the vast majority of shooters who would use this particular handgun, pulling a sub-3-inch group (i.e. tight enough to be able to be zero'ed from) at that distance is going to be much more about shooter skill than it is about the cartridge's nuances.
This is ostensibly why Dawson Precision (more in a minute) asks shooters to zero at the 20 yard line...because most shooters fall apart rather fast as they start to really push yardage.
[
Towards this, modern defensive/duty-caliber handguns -from full-size to sub-compacts- zero'ed at the 25 will be able to engage "POA/POI" easily from 3 (think the late TLG's version of Dot Torture) to 100 yards (not uncommonly pushed yardage in "walk-back" drills or contests). ]
Similarly, you'll notice that instead of just using language, SA's technical writers shows a visual. This is important because language often gets in our way when we talk about the zero:
View attachment 24727
* Image stolen from all over the Interwebz.
^ ....in which both "Sight Image 1" and "Sight Image 2" are both often referred to by various shooters as "6-o'clock hold," and both "Sight Image 2" and "Sight Image 3" could be called "POA/POI." Because of the imprecision (sorry, no pun intended!
) of language, a picture here literally says a thousand words, and tends to get folks' thinking aligned much more quickly.
So with Night Fission saying that their standard OE-replacement sights will regulate as the gun's manufacturer intended, what they mean is just that: to look at how your handgun's maker intended things to be, with their factory setup.
They don't say anything about their suppressor-height sights, and I don't know why, However, as a "matched set," you really shouldn't have to worry much about the sights impacting drastically low or drastically high, understanding that with most modern duty/defensive handguns that the sights are usually regulated to either "Sight Image 2" or "Sight Image 3," at the 25 yard line, with typical commercial range and premium (i.e. defensive/duty) cartridges.
Usually, a drastic POA/POI shift comes from "mixing-and-matching" sight sets, either from different manufacturers or from within that manufacturer's product line's options.
Dawson Precision, whose sights are very highly regarded in the handgun world, gives good insight into this matter with their "Perfect Impact Policy" -
....and their online, interactive, sight height calculator:
dawsonprecision.com
As you see from the Dawson sight height calculator, typically, altering sight body dimensions to raise/lower to either correct or refine POA/POI is done by changing the height ratio between the front post and the rear notches. Here's another, possibly more intuitive view of what's going on within the calculator -
View attachment 24728
* Image taken from 1911Addicts, but it's again all over the Errornets!
And the question becomes even more muddled when folks aim by "aligning the dots," versus the actual sight bodies:
View attachment 24729
* Picture taken from ARFCOM thread - https://www.ar15.com/forums/Handgun...nt-sights/13-186208/?page=1&anc=bottom#bottom
^ Here, note the discrepancy between sight blade alignment and dot alignment.
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All of this, really, is just to say that what you posted earlier about getting out and putting rounds downrange is truly what you'll both want to do and have to do.
Google-Fu shows that rounds impacting low (at 7 yards and closer) by 1.5 to 2-inches is a not uncommon complaint from shooters who recently installed suppressor height sights. However, it's almost never clear if this is just that they are not taking into account the differences in terms of how their new aftermarket sights are regulated versus their factory setup, or if they actually had to pursue corrections/remediation with the aftermarket sight manufacturer.