Zeroing flip up sights? [Archive] - Glock Talk

PDA

View Full Version : Zeroing flip up sights?


ElectricZombie
01-04-2010, 23:47
I recently set up one of my AR15s with an EO Tech and a simple backup rear sight. This backup sight is windage adjustable only, so I'll have to adjust the front sight.

What distance do most people sight their backup sights in for?

BOSS302
01-04-2010, 23:52
100m IMO.

lawman800
01-05-2010, 01:41
100 metres. Same as the EOTech recommendation for their HWS.

NeverMore1701
01-05-2010, 06:41
50m, that way you're back on at 200m, with no more than a couple inches deviation from 0-300m.

X-Spec
01-05-2010, 08:53
50m, that way you're back on at 200m, with no more than a couple inches deviation from 0-300m.

+1 This will give the flattest trajectory giving least deviation out to 300 meters.

Chuck TX
01-05-2010, 09:05
I do 50/200.

MCKNBRD
01-05-2010, 09:16
Oh, and FWIW, pick one rear aperture and stick with it. If you flip the rear aperture (like on standard A2-style sights, anyway) it does affect windage. Not noticeably inside 100yds, but past that you can be 3-4" off per 100yd, IIRC.

Byrdman

KalashniKEV
01-05-2010, 10:19
25m... just like the Army.

A lot of folks don't print tight enough to zero a red dot or irons at 100m... unless they have:

1) A magnifier or super eyesight
2) A suuuub MOA shooter
3) Skillz

They'll say it's zeroed but it's really "shot cluster adjusted" and that's not the standard.

http://www.globalsecurity.org/military/library/policy/army/fm/3-22-9/image1604.jpg

A 25m zero will put an M4 on at 300m and a M16A2 on shy of 350m using M855 ammunition. Highest trajectory in between is ~5-9"

Norcal911
01-05-2010, 11:12
KalashniKEV, I would like to respectfully disagree with you. For urban combat, 9 inches is plenty off to miss a head shot when needed and the average police sniper engagement is like 60 yards. That's the average for a SWAT sniper, its way lower for a patrol rifleman, I think the 50 yard zero is the way to go. If you zero at 25 then you need to teach your people range estimation and to hold off in relation to where your shot is vs. your 25 yard zero. If zero'd at 50, all I have to do is teach them to make up for sight offset as they become extremely close to the target. They will very likely never take a shot beyond 50. This would likely be different if you were in the sandbox or maybe you were a rural cop. Alaskapopo, I'm assuming you are rural, what zero do you use?-Norcal911

KalashniKEV
01-05-2010, 11:52
For urban combat, 9 inches is plenty off to miss a head shot when needed and the average police sniper engagement is like 60 yards.

"Know your weapon and it's POA/POI" is a given, but I think you've painted a very specific, niche scenario that supports your assertion.

I'd also recommend you take a second look at the trajectory chart, which shows that a 25m zero gives you a maximum 2" offset out to 50m (you stated up front that "police snipers" typically make an avg. 60m (or across the street) shots.

25m zero is definitely the way to go for all around use, and that is the general advice I give. I support that one may see fit to take that in or out to suit specific needs, but the OP didn't state that he would only be shooting in close.

luv2brode
01-05-2010, 12:46
i go 25 meter with a gi zero target old habits, if it aint broke dont fix it

faawrenchbndr
01-05-2010, 12:54
i go 25 meter with a gi zero target old habits, if it aint broke dont fix it

This works for me,........:supergrin:

Norcal911
01-05-2010, 14:05
K, point taken. I'll stick to my 50 yard zero just because its less variation and I'm comfortable with it. Obviously the 25 yard zero works, I used it for 7 years in the Army. This is a hotly debated topic and I think we may be splitting hairs. I'm curious if the military has changed from the 25 yard zero as their battlefield has changed from long range to much shorter urban style engagements in the last 10-20 years?-Norcal911

KalashniKEV
01-05-2010, 14:24
K, point taken. I'll stick to my 50 yard zero just because its less variation and I'm comfortable with it. Obviously the 25 yard zero works, I used it for 7 years in the Army. This is a hotly debated topic and I think we may be splitting hairs. I'm curious if the military has changed from the 25 yard zero as their battlefield has changed from long range to much shorter urban style engagements in the last 10-20 years?-Norcal911


Nope... 25m is still the standard and always will be. I also think the whole "urban combat" trend is overstated in Internet lore. In Afghanistan there are PID'd hostile targets that are so far away they can only be engaged by company mortars. I've been everywhere in Iraq except for out West and even in urban centers there were always longer shots to be had/made in both directions.

Flinter
01-05-2010, 18:56
I agree with KalishniKev

nipperwolf
01-05-2010, 19:21
50m, that way you're back on at 200m, with no more than a couple inches deviation from 0-300m.

Agree with the 50yd zero. Good to go from 0-200. I prefer a 2-3" variance, instead of 10". It really is that simple.

Paul Gomez
01-10-2010, 20:59
Neither the Army nor the Marine Corps use a 25M zero.

Mnukedude
01-10-2010, 23:58
I use a 50 yard zero myself.

ottomatic
01-11-2010, 12:29
Another vote for 50 yards. Up to a little over 200 yards, everything will be plus or minus 2.5"

Alaskapopo
01-11-2010, 13:58
I recently set up one of my AR15s with an EO Tech and a simple backup rear sight. This backup sight is windage adjustable only, so I'll have to adjust the front sight.

What distance do most people sight their backup sights in for?

50 yards same as you should do any optics without a bullet drop compensator requiring a 100 yard sight in. A 50 yard 0 puts you on at 200 yards and only 2.5 inches high at 100 if you are using 55 grain ammo. A 100 yard 0 puts you low at all ranges except 100 yards.
http://i59.photobucket.com/albums/g299/355sigfan/100yardzero01.jpg

http://i59.photobucket.com/albums/g299/355sigfan/improvedbattlesightzero01.jpg
http://i59.photobucket.com/albums/g299/355sigfan/300meterzero01.jpg
Pat

Alaskapopo
01-11-2010, 14:01
Nope... 25m is still the standard and always will be. I also think the whole "urban combat" trend is overstated in Internet lore. In Afghanistan there are PID'd hostile targets that are so far away they can only be engaged by company mortars. I've been everywhere in Iraq except for out West and even in urban centers there were always longer shots to be had/made in both directions.

The problem with the 25 yard zero is your shots are about 4.5 to 6 inches high at 100 yards making it possible to miss a partial target completely like say an enemy's head sticking up over cover with a rifle.
Pat

Alaskapopo
01-11-2010, 14:05
Take a look at this below.





An Improved Battlesight Zero for the M4 Carbine and M16A2 Rifle

1. Current Army/Marine Corps battlesight zero and it's procedures are well described in TM9-1005-319-10, the M16/M4 operator's manual. A recent copy of this manual is available for download at the Manual Depot. Procedures in the manual will not be repeated here.

2. The current 300 meter battlesight zero is a function of the sights on the rifle and I personally find it shoots too high for the vast majority of combat targets, including the Army's qualification ranges. The procedure listed here takes better advantage of the flat trajectory of these rifles as well as the use of civilian ranges, which are seldom surveyed in meters.

3. When zeroed at 200 meters, a distance twice that of normal combat engagements, these rifles have a very flat trajectory that is less then 2" from line of sight at all intermediate distances; a distance that's smaller than the normal dispersion of arsenal or factory loaded ammunition. This tiny trajectory arc allows very precise shooting out to 250 meters where the bullet is only 2" below line of sight.

4. A 200 meter zero has the happy coincidence of an initial trajectory cross-over at 50 yards, a distance available on almost all civilian ranges including many indoor ranges. This makes it easy to achieve a 200 meter battlesight zero without recourse to surveying your own range. If 200 meters is available you can fine-tune the zero at the real distance. And should when you get the chance.

5. The lowest sight setting, however, on these sights is 300 meters so the sight needs to be modified to preserve the markings on the sight (despite the fact that no one ever sets a range on these in the real world other than a USMC range). The sight needs to be set to bottom out at 8/3 -2 clicks. This will be the new 200-meter setting.

1. Flip the rear sight back to the unmarked aperture. This will reveal a hole in the top of the handle.

2. Rotate the sight wheel all the way down. Will probably be exactly at 8/3 (6/3). Don't force it down.



3. Using a 1/16" Allen wrench loosen the screw (under the revealed hole) in the sight wheel 3 full turns. Leave the wrench in the screw.

4. Rotate the bottom half of the sight wheel two clicks clockwise. This will raise the sight body if you look at it while you're turning it.

5. Tighten the Allen screw, remove the wrench, and confirm the sight bottoms out at 2 clicks BELOW 8/3. If not repeat the procedure until it's right.

6. Battlesight the rifle per the -10 with the following exceptions:

1. Sight should be at 8/3 -2 clicks, that is, all the way down, not up a click. Please note removable handle sights are marked 6/3 (rather than 8/3); also some are in ‘half-clicks’ as well. There should be 3 clicks between 3 and 4 on the knob. If there are 6 clicks then the sight needs to be set at –4 clicks (instead of –2).



2. Small aperture, nose to firing handle weld.

3. Distance is 50 yards.

4. Point of aim should be point of impact of bullet.

7. Remember you're adjusting the FRONT SIGHT for elevation, not the rear, and that each click is about 1/2" (actually a little more) at 50 yards. You won't get it closer than that. Don't frustrate yourself trying.

8. You're done. Leave the sight in this position for 99% of your shooting.

9. If you have to shoot targets you KNOW are 300 meters away or more, just click to the right number on the sight.

10. If you're patrolling, set the sight to 8/3 and snap the aperture forward to 0-2. This will provide the same trajectory as above but with a larger, easier to see thru rear sight. Use this setting if you also have the M68 mounted as it's quicker to transition to if the sight fails. [Editor's Note - there is some variance with the offset of the A2 aperture - they SHOULD be a 2 click difference - however some manufactures produce them with larger offsets. Setting the sight to 3 then flipping to 0-2 might now work for your AR. Check it at the range, you want the group to be centered at 50y, you might need to set the sight at 3 +2 or even 4 to get the large aperture to be correct]

11. If you have an M68 CCO (Aimpoint CompM-XD) optical sight battlesight it to 50/200 as well. You can shoot to 300 meters by merely holding "over a dot."

12. This battlesight zero is valid to 300 meters for both the M16A2 and M4 Carbines and their AR15 sisters. It's valid with any ammunition that approaches the specs for M193 (55gr) or M855 (62g) Ball ammunition. It works for both rifles and carbines due to the offsetting influence of higher muzzle velocity in the rifle being offset by the longer sight radius that moves bullet strike less per click. This is battlesight, not X-ring shooting!

13. This battlesight zero does not reflect the doctrine of the US Armed Forces, however, it reflects the personal use of these weapons in combat and in training for over 34 years.

14. Comments to: Lt. Colonel Chuck Santose (santose@compuserve.com).

Original document: 990104

Copyright 1999, 2000. All rights reserved.

Click here for some feedback on the IBSZ from US Soldiers.

Note To Users of Carbines with the A1 style rear sight or users of Flip-Up Sights: This 50 yard zero works really well. If you have the original sight aperture use the unmarked (short range) hole to zero the rifle. If you have upgraded, and use the A2 style aperture (or the A.O. Same Plane sight), then use the small (long range) hole for zeroing.

Thanks to Scott Thompson for sending this to us.

luv2brode
01-11-2010, 14:39
Neither the Army nor the Marine Corps use a 25M zero.
guess i was on the wrong range with the wrong target all them years.

faawrenchbndr
01-11-2010, 14:55
Good stuff Pat!

ChaneyD
01-11-2010, 15:16
I agree with KalishniKev

Ditto! 25m and you're dead on at 300m

ChaneyD
01-11-2010, 15:20
Neither the Army nor the Marine Corps use a 25M zero.

According to Army FM3-22-9 dated 4/24/2003, 25m is STILL the zeroing distance. Hasn't changed since WWII.

Alaskapopo
01-11-2010, 16:24
"Know your weapon and it's POA/POI" is a given, but I think you've painted a very specific, niche scenario that supports your assertion.

I'd also recommend you take a second look at the trajectory chart, which shows that a 25m zero gives you a maximum 2" offset out to 50m (you stated up front that "police snipers" typically make an avg. 60m (or across the street) shots.

25m zero is definitely the way to go for all around use, and that is the general advice I give. I support that one may see fit to take that in or out to suit specific needs, but the OP didn't state that he would only be shooting in close.

50 yards is much better for all around use. You don't need to shoot past 200 much at all but the need to take a 100 yard shot is not that remote and having to aim 6 inches low to make it its unacceptable.
Pat

lawman800
01-11-2010, 20:51
Wait... before we get all technical on 25m zero going to 300m or 50m is dead on at 250m... what distances will the OP realistically engage a threat?

I will not likely take a shot beyond 25 yards myself with the standard issue Mini-14 and open sights. I have no idea where the sights have been or when's the last time it was zeroed.

If I zero in at 25 yards, I can hold over at 50 yards at still be able to hit COM hopefully if I have to. Beyond 50 yards, I am not taking a shot unless it's for suppressing fire or I am sure of the backstop and there's no alternative like having a sharpshooter on scene by then.

Alaskapopo
01-11-2010, 20:55
Wait... before we get all technical on 25m zero going to 300m or 50m is dead on at 250m... what distances will the OP realistically engage a threat?

I will not likely take a shot beyond 25 yards myself with the standard issue Mini-14 and open sights. I have no idea where the sights have been or when's the last time it was zeroed.

If I zero in at 25 yards, I can hold over at 50 yards at still be able to hit COM hopefully if I have to. Beyond 50 yards, I am not taking a shot unless it's for suppressing fire or I am sure of the backstop and there's no alternative like having a sharpshooter on scene by then.

You are missing the point. If you zero at 25 you will actually have to hold under at 50 and 100 yards. The bullet is climbing. However if you zero at 50 yards you are going to be within 2.5 inches of your point of aim from 0 to 200 yards give or take some yardage depending on your load. The 50 yard 0 is the easiest to use in real life because you just aim and shoot without worrying about hold over or hold under until you get past 200 which is pretty rare in LEO work.

LLL
01-11-2010, 21:33
25m... just like the Army.

A lot of folks don't print tight enough to zero a red dot or irons at 100m... unless they have:

1) A magnifier or super eyesight
2) A suuuub MOA shooter
3) Skillz

They'll say it's zeroed but it's really "shot cluster adjusted" and that's not the standard.

http://www.globalsecurity.org/military/library/policy/army/fm/3-22-9/image1604.jpg

A 25m zero will put an M4 on at 300m and a M16A2 on shy of 350m using M855 ammunition. Highest trajectory in between is ~5-9"

question, m4 is 16 in barrel a2 is what length barrel????
LLL

Mnukedude
01-11-2010, 21:36
guess i was on the wrong range with the wrong target all them years.

I think I was too.

Mnukedude
01-11-2010, 21:37
question, m4 is 16 in barrel a2 is what length barrel????
LLL

M16A2's feature a 20 inch bbl

lawman800
01-11-2010, 21:46
You are missing the point. If you zero at 25 you will actually have to hold under at 50 and 100 yards. The bullet is climbing. However if you zero at 50 yards you are going to be within 2.5 inches of your point of aim from 0 to 200 yards give or take some yardage depending on your load. The 50 yard 0 is the easiest to use in real life because you just aim and shoot without worrying about hold over or hold under until you get past 200 which is pretty rare in LEO work.

You're right... it's hold under at 50 yards when zeroed for 25 yards... it's been a long day.

I don't know your jurisdiction, but realistically, in our suburbs, taking a shot at 25 yards and beyond would be a rarity due to the congestion and lack of a clear backstop.

Alaskapopo
01-11-2010, 21:57
question, m4 is 16 in barrel a2 is what length barrel????
LLL

Actually an M4 is a 14.5 inch barrel and a M16 A2 has a 20 inch barrel.
Pat

Alaskapopo
01-11-2010, 22:00
You're right... it's hold under at 50 yards when zeroed for 25 yards... it's been a long day.

I don't know your jurisdiction, but realistically, in our suburbs, taking a shot at 25 yards and beyond would be a rarity due to the congestion and lack of a clear backstop.

We had a situation once where there was a bad guy popping rounds off at people inside a national park (next to our jurisdiction) We ended up doing most of the work because the Troopers only had 2 people on and the Forest Service was not equiped to handle something like that. Anyway it all ended well but we were looking at distances of 200 to 260 yards. My point was its actually easier to zero at 50 and be prepared for everything you might ever be expected to handle with no downsides. The 25 yard 0 is actually a 300 yard 0 and the down side is you are 6 inches high at 100 yards.
Pat

Wild Gene
01-11-2010, 23:37
When you sight at 25M, you are using the small app on the A2 sight, and setting the elevation to 300M plus one click. Shooting at 25M, this allows the sight to calibrate out, and you can see the bullet strike easier than at farther distance, and the closer distance takes out the precision necessary for the longer Zero. (Face it, it is easier to fire a sub one inch group at 25M than 100M.)

Take the large app, set elevation down all the way and shoot at 25 yards, you shouldn't be hitting dead on anymore. They use 25M becasue that is what works with the sights, allowing the multiple elevation setting to work.

The A2 sight is dual aperature and dual plane, you need to remember that many flip up "backup" sights, like the ones from Troy Industries, are dual apperature, but single plane. For that, I'd go 50, it will give you a better Maximum Point Blank Range (the distance you can hold dead on, and never vary more than about three inches above or below the line of sight). I believe it is about 273 yards.

I have been wrong before. Like all else, know the ballistics of what you're shooting, practice, and try not to second guess the rifle.

Take care!

luv2brode
01-12-2010, 09:14
the way i remember is zero at 25 for 300, if done correct yes you may be a little off but hopefully will have more of the target in the open.

sgtlmj
01-12-2010, 09:21
50 yards

engineer151515
01-12-2010, 10:17
Don't know if this helps, but 50 meters is approx 54 yards, 2 feet.

Wild Gene
01-12-2010, 11:29
You are shooting 25M to zero, but you are using the small apperature (sp.), and setting the elevation at 300M plus one click. This allows the elevation and dual plane appature to function. Most flip up "backup" sights are dual app but single plane. Take your A2 sight, zero it at 25M, then lower the elevation to 100-200, with the large apperture and shoot at 25M, you will not be hitting in the same place on your target.

I would go with 50yards on the single plane sight, this would put your Maximum Point Blank Range at around 250 yards. This way, you can hold dead on out to that range and your bullet will never travel more than 3" above or below your line of sight out to that distance.

KalashniKEV
01-12-2010, 13:52
question, m4 is 16 in barrel a2 is what length barrel????
LLL

An M4 has a 14.5" barrel. An M16A2 has a 20" barrel.

KalashniKEV
01-12-2010, 14:04
Most flip up "backup" sights are dual app but single plane.

The standard BUIS is the MATech, single aperture. It does have a goofy elevation adjustment though, which renders a lot of this moot.

I keep it on the zero line and don't adjust, although I've contemplated cranking it all the way down to 600m and then still not adjusting. It just seems more secure that way.


Take your A2 sight, zero it at 25M, then lower the elevation to 100-200, with the large apperture and shoot at 25M, you will not be hitting in the same place on your target.

I may be wrong, but I don't think the apertures are graduated like on an HK diopter sight...

KalashniKEV
01-12-2010, 14:08
Neither the Army nor the Marine Corps use a 25M zero.

AAAAAAAAAAAAAAAAHHHHHHH!!!!!!!!!!!!!!

My head aspode.

Refer to 5-1 of 3-22.9...

http://www.scribd.com/doc/344690/M16-Rifle-Marksmanship

Now all your questions regarding zero are answered!

= )

faawrenchbndr
01-12-2010, 14:26
Neither the Army nor the Marine Corps use a 25M zero.

You keep thinking that! :rofl:

Wild Gene
01-12-2010, 15:30
K,

I know my bushmaster has dual app. the large one for up to 200M, and the small one for 300 plus. My Backup sights on another rifle (they are troy ind.) are dual app., but the single plane.

As far as the Military, and a 25 yard Zero, and having never served, and thank you for all of you that have, If you zero at 25M (which you are clearly instructed to do), but use the procedure (25M target, Small App., 300M elevation plus one click), you are shooting at 25M, but technically your not zeroed at 25M when using the larger, 100-200 app., are you? I read the source you referenced, man the army sure can make things confusing to us "civillian farmer" types. I am going to go get the lead sled and do some experimenting.

I believe the military zero provides for a larger Maximum point blank range variance (plus or minus 4.5" where as I like to keep mine at 3" above or below my line of sight), and of course, what an individual chooses really depends on what he is shooting at. A red digger is about 2.5" tops but an elks zone is more like 9".

Very interesting thread. I appreciate it you guys.

Take Care.

KalashniKEV
01-12-2010, 16:42
K,

I know my bushmaster has dual app. the large one for up to 200M, and the small one for 300 plus.

So what do you do when a target presents itself from 200m to 300m?

= )

The O-2 Aperture is generally for low-light or mask fire only. 3-22.9 even says to ensure it's down before zero procedures can begin.


technically your not zeroed at 25M when using the larger, 100-200 app., are you?

The O-2 aperture is not graduated for closer range, only larger for faster acquisition. You should still be zeroed after you flip it b/c it doesn't ride the thread of the windage screw.

Molon
01-12-2010, 17:46
0-2
http://i672.photobucket.com/albums/vv81/gocartmozart2/largeaperture01coloredpencilresized.jpg



There seems to be some confusion around here as to the function of the “0-2” large aperture of the A2 rear sight. The field manual for M16A1 and M16A2 Rifle Marksmanship states, “The larger aperture, marked 0-2, is used for moving target engagement and during limited visibility." That's clear enough. "The unmarked aperture is used for normal firing situations, zeroing and with the elevation knob for target distances up to 800 meters. The unmarked aperture is used to establish the battlesight zero.” That’s pretty straightforward.

Using a digital caliper, the diameter of the small aperture of the A2 rear sight measures approximately .070”. The large (0-2) aperture has a diameter of approximately .200”. No confusion there.

To use the 0-2 large aperture, simply push forward and down on the small aperture portion of the sight leaf to snap the large, 0-2 aperture up into place. That couldn’t get much easier.

The confusion surrounding the use of the 0-2 large aperture seems to stem from a misunderstanding of the amount of elevation change involved when changing from the small aperture to the large aperture. The small aperture is intended to be zeroed for a 300 meter zero using M855 fired from a 20” barreled M16A2. The 0-2 large aperture is intended to provide a 200 meter zero, when the small aperture has been properly zeroed with M855 from a 20” barreled M16A2. If you examine the trajectories of M855 fired from a 20” barreled M16A2 zeroed at 300 meters, and at 200 meters, you will see that the difference in elevation between these two trajectories (and hence the difference in elevation between the small and large apertures) is 2.5 MOA.

http://i672.photobucket.com/albums/vv81/gocartmozart2/smallversulargeaperturetrajectories.jpg





To demonstrate this concept, I fired two 10-shot groups from a 20" Colt AR-15, using the standard A2 iron sights, from the bench at a distance of 50 yards using the small aperture. I then flipped the rear sight to the 0-2 large aperture and fired another two 10-shot groups (all groups were fired on separate targets.) The two sets of groups were overlayed on each other to form 20-shot composite groups using RSI Shooting Lab and analyzed to determine the statistical center of their points of impact.

In a perfect world, the groups fired using the 0-2 large aperture would have the center of their points of impact 2.5 MOA (1.25” at 50 yards) below the center of the the points of impact of the groups fired using the small aperture. The 20-shot composite group formed from the 2 groups fired using the 0-2 large aperture had a center of point of impact 1.01” below the center of point of impact of the 20-shot composite group fired using the small aperture. 1.01” at 50 yards is 2.02 MOA; not exactly 2.5 MOA, but within a half minute of angle and well within my margin of error using the A2 iron sights. As a side note, the groups fired using the 0-2 large aperture were 144% larger than the groups fired using the small aperture.

http://i672.photobucket.com/albums/vv81/gocartmozart2/rifle9resized2.jpg

Wild Gene
01-12-2010, 18:12
Honestly, my A2 sights are different. They are dual plane, meaning the center of the smaller hole is higher than the center of the larger hole.

Now I am second guessing myself. I am going to have to go look, and if I am wrong, you will be the 2nd to know....

Wild Gene
01-12-2010, 18:16
Molon,

I think your last line demonstrates why they use the 300+one click and the small app. to zero at 25M. It allows more precision for the sighting in.

WG

Wild Gene
01-12-2010, 18:58
I went and tried to measure the height of the center of the two apps.. I don't have the instrument to do a really accurate measurement, but it appears to be about the thickness of the line on my rule.

There is also a difference in the zero procedure between the A1 and A2 sight.

My bushmaster book does show a difference in trajectory using the small vs. the large app.

Have a great evening.

tebklr
01-12-2010, 19:58
Take a look at this below.

An Improved Battlesight Zero for the M4 Carbine and M16A2 Rifle
<snip>
Thanks to Scott Thompson for sending this to us.

Pat -- It may not be like the Armed Forces do it, but it makes a lot of sense for my uses. Thanks for the info. Duly copied and saved.

Hope my crappy DPMS will shoot long enough to get this done! :tongueout:

Tom

Molon
01-14-2010, 10:16
I went and tried to measure the height of the center of the two apps.. I don't have the instrument to do a really accurate measurement, but it appears to be about the thickness of the line on my rule.



The reported elevation offset between the two apertures for a mil-spec sight is 0.014".

Wild Gene
01-14-2010, 17:00
Molon,

Thanks! Amazing, isn't it. Would that be something like 2.1" if extended out to 300M above line of sight? (roughly .5Mx.014"x300M, assuming .5M between front and rear sight on a rifle). It astounds me that our eye can line up the front and rear sights with such precision to make any difference at all, let alone fire MOA groups.

Take care.