POI Using Iron Sights at Various Distances

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Chief TC

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I thought this might be the right forum to ask this question. As some background, I am starting to get into competitive shooting and practicing a lot on honing loads for a variety of rifles. I am mostly focusing on BPCR using vernier sights but I want to ask about using rear aperture and blade sights. Question is - If my POA is 6 o'clock hold on any given target and POI in 8 inches above POA, does this mean at all distances with the proper MOA adjustment, the POI is always going to be 8 inches above POA?

Sorry if this is a stupid question, not a big math guy but I am capable of learning. Thanks.
 
Chief TC said:
not a big math guy
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I'm not a rifle guy, but from the math stand point that won't hold true as the flight characteristics of the bullet well change the POI at different distances.

Sorry...even re-reading that sounded awkward.

But the answer to your initial question is still negative
 
does this mean at all distances with the proper MOA adjustment, the POI is always going to be 8 inches above POA?
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Yes, with a caviot. If the rifle, ammo, distance and wind stay the same. Yes.
If you add distance, the POI will be lower. Reduce distance, higher, generaly.
If you make a MOA correction for your distance change, thats your rifles "DOPE" for that distance.

Another POI (Point of interest) On NRA high power targets, the aiming black is always the same MOA.
size varies from distance to distance, but the MOA is always the same. Ponder that. ;)
So, as a measurement aid, the aiming black is always 6 MOA. Kind of a ruler for ya when you wonder how much to twiddle the sites.
Practice that and it will all make sense later.

200 yard target = aiming black is 13 inches. 6 MOA
100 yard target = aimong black is 6 1/5 inches 6 MOA again
 
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9mmepiphany said:
I'm not a rifle guy, but from the math stand point that won't hold true as the flight characteristics of the bullet well change the POI at different distances.

Sorry...even re-reading that sounded awkward.

But the answer to your initial question is still negative
Click to expand...
OK, that makes sense.
DustyRusty said:
Yes, with a caviot. If the rifle, ammo, distance and wind stay the same. Yes.
If you add distance, the POI will be lower. Reduce distance, higher, generaly.
If you make a MOA correction for your distance change, thats your rifles "DOPE" for that distance.

Another POI (Point of interest) On NRA high power targets, the aiming black is always the same MOA.
size varies from distance to distance, but the MOA is always the same. Ponder that. ;)
So, as a measurement aid, the aiming black is always 6 MOA. Kind of a ruler for ya when you wonder how much to twiddle the sites.
Practice that and it will all make sense later.

200 yard target = aiming black is 13 inches. 6 MOA
100 yard target = aimong black is 6 1/5 inches 6 MOA again
Click to expand...
This helps a lot as well. Thanks! And I realize you have to take into account for inclines and declines of shooting angle if the targets at not on the same terrain.
 
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You didn't ask but I'll mention; you also need to take into if lighting conditions change, such as the sun coming out from behind clouds. "Lights up, sights up" is how it is commonly phrased. Watching the mirage is another critical aspect.
 
Russ57 said:
You didn't ask but I'll mention; you also need to take into if lighting conditions change, such as the sun coming out from behind clouds. "Lights up, sights up" is how it is commonly phrased. Watching the mirage is another critical aspect.
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Actually this is the first I’ve heard of lights up, sights up. I do account for lighting conditions but mostly in regards to the aperture size and low light. I’m trying to think about mirage more.
 
Chief, in a nutshell both make the target seem to be in a different place than it was before the change occurred. I'll leave you to read up on the topics.

A good spotting scope is an essential tool IMHO. Since I shoot with a scope my spotting scope is never focused at the target.

There are a lot of tricks/things to learn. I suggest a journal and make sure to note dates/times/weather conditions.

Oh, and be very wary of the guy that remarks on your target in a match, doubly so if he offers you a soda or coffee.
 
Chief TC said:
If my POA is 6 o'clock hold on any given target and POI in 8 inches above POA, does this mean at all distances with the proper MOA adjustment, the POI is always going to be 8 inches above POA?
Click to expand...

If by "proper MOA adjustment" you mean accounting for the bullets trajectory (drop), of course it will. Why would it be any different than applying the same elevation adjustment to keep scope crosshairs centered in a bullseye at different distances? One cause of confusion when using a 6 o'clock hold is that the physical size of the target gets progressively larger with increasing distance. Therefore, you must account for the increased distance from the bottom of the target to the center, plus the bullet drop.
 
Laphroaig said:
If by "proper MOA adjustment" you mean accounting for the bullets trajectory (drop), of course it will. Why would it be any different than applying the same elevation adjustment to keep scope crosshairs centered in a bullseye at different distances? One cause of confusion when using a 6 o'clock hold is that the physical size of the target gets progressively larger with increasing distance. Therefore, you must account for the increased distance from the bottom of the target to the center, plus the bullet drop.
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This is how my non-mathematical brain understood it but sometimes what we think makes sense does not add up mathematically.
 
Maybe you are aware of this, but, years back when shooting service rifle, blackening the font sight with a carbide flame was a big help on sunny days. Adding to what Russ57 said, I likened it to the suns glare making part of the sight invisible. Enough to change the point of impact. And if the sun is on and off, it's worse. Blackening the front sight area helped eliminate that glare. A carbide lamp was popular then and maybe still.
 

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Jim Watson said:
Yes, you could adjust your sights to a "proper" setting to hit 8" high at whatever range.
Keep a notebook of sight settings for different ranges.
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Right and I do that with vernier sights, but if I am using static military sights then you can't adjust to that specificity.
 
Jim Watson said:
What kind of military sights? One of the several Springfields, or a Sharps "buckhorn" or Lawrence?
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The sights on 1903A3 are every 50 yards and 1917 are every 100 yards, so you can't dial it in to that specificity. And while there is a rear aperture, a front post makes it a little more difficult to gauge where you should put POA. At least for me.
 
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If your POA is a six o'clock hold at 100 yds and the POI is 3" higher; the POI is 3 minutes higher than the POA. Therefore at 200 yds 1 minute = 2" so the POI would be 6" higher than the POA..... 600 yds the POI is 18" higher than the POA. So on and so on.
 
Bronco72 said:
If your POA is a six o'clock hold at 100 yds and the POI is 3" higher; the POI is 3 minutes higher than the POA. Therefore at 200 yds 1 minute = 2" so the POI would be 6" higher than the POA..... 600 yds the POI is 18" higher than the POA. So on and so on.
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You would think so but that is not how it works based on how the sights are designed. I can shoot my milsurp rifles at 200, 300 and 400 yards and this does not apply. So whatever MOA calculation was done when they designed the sights does not follow this ballistic trajectory. From best I can tell, it seems the MOA calculation used was to put the POI at about the same above POA at short to medium distances.
 
It worked on my M1A when I was competing at 200, 300 add 600 yards ! That was with the military site on it !
Of course you have to adding minutes of elevation to account for the distance. For instance if POA at is six o'clock hold on bullseye and POI is 6" higher a 200 yds. the difference is 3 minutes
 
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I think it is how your sight was designed. The sight on my 1903A3 has the same 8” above POA 200,300 and 400.
 
Bronco72 said:
So you don't raise your rear sight when going from 200 to 400 yards ??
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I do. I set the sight to the designated distance. That is part of why I asked the original question. I am not a math guy but I understand all the basic mathematical principles, using vernier sights and ballistics. I was trying to determine and understand why and how some iron sights are designed. Vernier sights can be adjusted to less than half MOA, so you can always adjust your sight to be on the bullseye regardless of distance. I’ve never found different models of guns’ sights to be designed equally. My M1917, M1 Garand and M1903A3 all shoot differently when you compare them by POA vs POI. None of my rifles does what your M1A does. So this does show, IMO, that different models of sights are designed differently.
 
Chief TC asked: does this mean at all distances with the proper MOA adjustment, the POI is always going to be 8 inches above POA?
Broco72 was correct on the inches. I was thinking MOA but talking inches. Sorry.
Talking MOA, it's a proportional thing. On official HP targets, the aiming black is always 6 MOA no matter how many inches it actually is.
Inches are always inches whether the ruler is in you hand, or 600 yards away.
🥴
 
I am having a hard time explaining! Maybe this will ?? Your POA never changes when sighting in a 6 o'clock hold on a bullseye; nor any target. You are always looking at the bottom of the black. Does not matter the distance. When adjusting the elevation of the sites you are changing the POI relative to your POA, You can adjust the POI to be anything from exactly the same as the POA OR higher or lower what ever you want. Works on any firearm and any sights, iron or scope. To say that the sites are always 8" higher any any distance does not compute! Unless you adjust the sites to be so!
 
Bronco72 said:
I am having a hard time explaining! Maybe this will ?? Your POA never changes when sighting in a 6 o'clock hold on a bullseye; nor any target. You are always looking at the bottom of the black. Does not matter the distance. When adjusting the elevation of the sites you are changing the POI relative to your POA, You can adjust the POI to be anything from exactly the same as the POA OR higher or lower what ever you want. Works on any firearm and any sights, iron or scope. To say that the sites are always 8" higher any any distance does not compute! Unless you adjust the sites to be so!
Click to expand...
On my 1903A3, POA is always 6 o'clock and POI is 8" above at 200, 300 and 400 yards changing to the approoriate sight settings. This must be how the sights are designed. Predetermined sight settings which is most iron sights does not allow anyone to adjust them to that specificity like a vernier sight. So what you are saying is that your M1A sight settings are designed that your POI increases based on MOA increase by distance - mine do not do that. I am interested why and how the sights are designed a certain way. I have no sights that do what your M1A sights do with exponentially increasing POI as you increase distance.
 
Chief TC said:
On my 1903A3, POA is always 6 o'clock and POI is 8" above at 200, 300 and 400 yards changing to the approoriate sight settings. This must be how the sights are designed. Predetermined sight settings which is most iron sights does not allow anyone to adjust them to that specificity like a vernier sight. So what you are saying is that your M1A sight settings are designed that your POI increases based on MOA increase by distance - mine do not do that. I am interested why and how the sights are designed a certain way. I have no sights that do what your M1A sights do with exponentially increasing POI as you increase distance
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I re-read this entire thread. I believe your initial question was hypothetical, right?
You were not actually describing what happened on the range for you at those ranges, right?
And your interest is Black Powder Cartridge Rifle (BPCR) Right?

My apologies, as I didn't immediately understand what BPCR meant. And my initial answer was incorrect regardless.
I am willing to share what I do know with any of the specific rifles you mentioned.
 
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