I was never able to make full sense, of the two apertures on a carry handle, or any other dual app sight for that matter.  I am of the very firm opinion, that you should be able to shoot irons, and do it well before anything.  

Shooting the small aperture, I have always been able to hold 3-4'' at 100, with half assed decent ammo.  But it seems that if it flip it to the big aperture, it is all off.  POI may be up, down, left or right.  Are they not supposed to be able to be switched?  Should I just sight it in at 50, with the big, and call it good?  This has been 6 or 7 years in the making, I have just gotten around to making an issue out of it.  

Thanks for the assistance guys.

Big aperture for close, little for far.

IIRC- big aperture= 0-299 yards, small aperture=300 on.

I think Magpul's app is a little bigger than the small dual app setup. I can still get 3moa @ 100yds with it and feel I still have a decent field of view for up close work. Big app I think is silly as I can basically hover over the sights and get the same accuracy with clear field of view. All in the technique I guess.

Yeah, but what he's saying is that the big ap makes it hard to shoot at 100 yards.  

I think this is an issue with eyesight.   My eyes bug out using the big ap when trying to shoot at any kind of distance.  For me, the big ap is best used for 25m  or low light in house clearing situations.  It is waaaaay faster to use, but I'm not very accurate with it at 100 yards either.  I can sort of  manage 50 yards.  But my eyes don't like it.  

I don't know what the status of your eyeballs are OP, or what, but that could contribute.  But it's obvious that the size of the ap affects accuracy.  The bullseye shooters use smaller aps than the normal small.  I do believe NM sights for the AR are smaller and hooded.  I know that NM aps are smaller for an M1A.

It might be a good idea to get a scope of some sort.  Even if it's a low power one.  I don't know.  Or just stick with the smaller ap and only use the big ap for like I said, danger close stuff.

To be honest, I've forgotten what the "technical" nomenclature of both apertures is (I swear, you guys are just conspiring to make me drag out all of my manuals ), but the combination is typically either referred to as a the "Ghost Ring" and "Peep Sight" apertures, or the large one as a "low light" aperture.  

If both are properly drilled, they should be "same plane," in other words, they should still have the same POA/POI regardless of which aperture you're using, however, I've heard that many aftermarket units are not necessarily properly drilled.  

That being said, the larger aperture - by virtue of being larger - allows for a lot more error on the shooter's part, which may be what is affecting your POI when using the larger aperture.

IIRC - and the way I use them - the proper procedure is to zero using the smaller aperture (at whatever your desired range is) - and then flip to the larger ghost ring aperture for combat.  Granted, I know of a lot of people who tend to just run with the peep "all the time," and as designed, the MATECH BUIS currently issued only has the peep aperture, but IMHO, the larger, ghost ring aperture is the superior "combat sight," as the larger size allows for faster target acquisition and rounds on target - if you need more precision and more distance, you almost invariably have the time to switch to the target aperture.  FWIW, when I did use BUIS, I preferred the KAC 300m for exactly this reason, because I would simply pop out the plastic peep sight insert, and use the larger ghost ring.  

The whole idea of the larger aperture as a "close range" or "CQB" aperture plays into this as well, and supports the idea that the larger aperture should be your "primary" aperture, as, by nature, closer threats will be more urgent, provide less reaction time, and often come as a surprise, meaning you want to have the appropriate aperture available immediately, without having to switch your sights when a close threat appears.  As I said above, distance buys time, which will allow you to move to the peep aperture if you need it.  

The smaller peep aperture is not only smaller, requiring a more precise alignment of the eye to get a sight picture, allows in less light, hence why some refer to the larger aperture as the "low light" aperture.  

The small peep is great for target shooting, and it's what I use, as I said, for zeroing and when grouping is my primary intent, but for a dynamic "combat" scenario, during, say, an assault through an objective, I personally feel that it's just too small to be useful.  And while most shooters will generally shoot less precisely with the larger aperture - it is still possible to shoot plenty accurately with the larger aperture, it just takes some practice/getting used, as the front sight post may seem to "swim" in such a larger ghost ring, particularly if you're used to the constricted view through the peep sight.  

Really, the person to ask about the "proper" employment of the dual apertures would be Lt Col Lutz (coldblue), as, like I said, I haven't pulled out my manuals, and it's been a long long time since I've considered iron sights my primary means of sighting, but this is the way I've done it.  

~Augee

I do believe that there is a designed POI shift in the A2 ap.  Just as there is in the A1 ap.  But of course the A1 aps are the same size.  One is marked for longer range and taller/higher.   I do believe my Colt manual says so.  I can go get it and see if you want me to.  Or maybe someone else will come along and confirm what I'm saying.  

IIRC the big ap is suppose to be zero'd for 0-200 yards, not 300.  Or is it meters?  Hmmmm.....  Maybe I will go get my Colt manual.  

Ugh, I stand corrected, I pulled out my colt manuals and I see nothing about it saying a difference in POI for the big to the little.  I remember a thread covering this a long time ago and I thought Molon and some others said it was part of the design.  I had done a little bit of testing myself, and found that there was a shift with my carry handle on a carbine.  Whether it's designed, or user error, or not designed but machined wrong, I don't know now.  I thought it was part of the design.  I'm PRETTY sure it is by design on an A1, otherwise there would be no need for two aps because they are both the same size.  No ghost ring.

I counter correct. Molon states in his archived post that the a2 aperture differs from the large and small on a vertical axis by 2.5 MOA.

FWIW, this this is a pretty good primer for the A2 rear sight.
chris

Guys, thanks for the input.  Here is my situation, so maybe it helps a bit.  Im 41, and my eyes are perfect.  I own scopes, I own Aimpoints, I own KAC BUIS,among others.  I own a lot of stuff, that hedges bets to speak.  The ammo I used for 3-4'' groups at 100, was M193.  Not match or anything special.  

I am just an obsessive type A personality, and refuse to not know something, or be able.  This is a S&W carry handle, which I guess is pretty well mil-spec.  The ghost ring seems to shoot a bit low, and maybe I just need a bit more trigger time, to make it all work right.  

I will go shoot it Friday, and report back my findings.  
Thanks again for all the work and effort.

Actually, I'm going to have to go with the counter-correction to myself.  

Looking through some other notes, it looks like there is a slight mechanical offset for range built into the 0-2 large ghost ring aperture.  



Makes sense, too - as I learned A2 iron sights from the Army.  

Goes to show how long it's been since I really relied on the A2 sight configuration for anything - and I was going off what I remembered from then, and chances are I wasn't taught 100% correctly, and never re-visited it in much detail.  

All I've known is the way I used the sights - zero on small, use large, switch if need be - I guess that means the coldblue's plan of a kind of dummy-proof setup where the end user doesn't need to fully understand why it works is borne out.  I used the bigger aperture on fire and maneuver live fire lanes and STX lanes, and it never failed to do what I asked it to do, so I didn't even think about the fact that the sight was giving me a slight mechanical offset to adjust for the ranges I was shooting at.  

~Augee

The thing is, I don't think the offset is enough to worry about.  When I zero'd my A2 the last time, I did as you say and used the small ap.  Now this was at the 60 yard range we have.  And I flipped to the big up to see if there was a shift, and I didn't notice any.  But this was with a 20"er, rifle length sights.  When I tested the carbine at   25 yards I noticed a difference.  With a detachable carry handle.

Point is: I think the different sight radius (carbine, mid and rifle) is going to have an impact on how much shift there is.  And then there is the sight itself, as you say, if it's in spec or not.  And then of course you can get "same plane" aps.  I think the troy flip up I had was.

Another thing I notice is that sighting is easier on my eyes using a rifle.  Both small and big ap.  My first AR was an a2 20"er and when I got my first carbine and used the irons, I was kind of  like what the heck.  When the font post was more blurry with the big ap.  It was annoying.