Can someone provide me with a link to literature stating that iron sights are shooter specific.  I am a LEO who is soon to be assigned to the training of the patrol rifle.  I know that they are designed for the individual shooter but would like a little documentaion to stand behind besides my personal expirence.

Thanks in advance

So you are looking for an individual iron sight for each rifle????

A-2 rear and FSB...let 'em learn..

And you are the instructor????

Basically my department is wanting to deploy a patrol rifle program.  I am a patrol rifle instructor and have met with my chief.  I told him that I recommended issuing the rifles to the individual officer VS putting them in the patrol vehicle.  I told him that its great to have a eotech or what ever sight they choose but the rifles need to have irons on them in case of a failure from the halo grahic sight they choose.  With that said I know that iron sights are a shooter based individual sight.  My chief is not really wanting to hear this so I wanted to show him something more concrete then what I learned in instructor school.  I have searched my instructor manuals and hav'e found anything to validate what I am trying to tell him.

Where did you get this idea?



There's a reason you aren't finding anything to validate it...





 

In my 56 years as a shooter, mostly with iron sights, I have never heard this theory. I suppose you could make an argument that older/weaker eyes could benefit from a smaller aperture closer to the eye to compensate for the loss of ability to focus easily at different distances. Younger/better eyes would not be so fussy, and could use a larger aperture, which would not be so limiting in low light. Other than that, what would you tailor to individual eyesight?

Also, I suppose that if one had really good eyesight one might be better off to use an open sight, especially a buckhorn style, at very close ranges. Some military training courses teach shooting over the rear sight if a very fast shot is required in a CQB scenario. A buckhorn sight would be better than shooting over the sight completely.

I'd be interested in having you elaborate on your original thesis. It is new to me.

EDIT: I know of no documentation to support your concept. Sorry!

I believe that what he means is that each shooter will have a specific approach to irons, making a "standard zero'd" set of irons result in different shooting results for a set of individual shooters.

Each may have a different cheekweld, or perception of what a proper sight image is (a shooter may be aiming off the top of the FSP versus another who tens to align it within the top body of the FSP, for example). Thus, a set of rifles that are properly zero'd according to one armorer/rangemaster may result in inconsistent results when used across a population of officers.

By assigning individual rifles, each officer will zero the sights according to his/her own sight picture/head position, etc. and have a rifle that will fire where he/she expects it to.

This variance is due to sight interpretation by shooters given ambiguous alignment alternatives presented by standard three point alignment iron sights, whereas a red dot optic makes head position etc. irrelevant.

Think of it this way - how many times has another trooper (or friend) handed you his rifle, which is perfectly zero'd according to his preferences, but you need to click a couple of adjustments to get dead center yourself?

I would think as the instructor you would be more inclined to recommend one style of back-up so the process for deployment and use is the same for everybody in an equipment failure situation. I can see an argument for the officer to pick his primary optic however, as many people with astigmatism have reported problems with certain optics and could be a problem for some if a specific optic was used on every weapon.

Topic Moved

Nevermind I misunderstood.

You pretty much hit the nail on the head of what I am trying to get at.  Each individual person will have a different cheek weld, touch reference etc.  I guy that is 5'6 will handle the weapon differently then a guy that is 6'1 and so forth.  I can give a person my weapong that is zero'd for me with iron sights and then hand it to someone else and he/she will have a different group pattern.

Also guys sorry for starting this in the wrong place.  I am new to the forum and I am just trying to get some clarification.  When I went to instructor school the lead instructor made all the guys attending trade rifles and shoot them according to the zero that was set specific to the gun owner.  NO ONE shot excatly like the person who had the gun before.  Some shot as far off as 6 inches in any direction at 50 yards.  What I am trying to do is prove that not every shooter will shoot the same with iron sights.  Yes with a halo graphic sight it may be different but everones cheek weld, touch reference, and distance from the rear sight may be different with iron sights.

Exactly.  I was just wanting a little more documentaion then "Hey this is what I learned in school."  The big issue here is money. 60 officers equals 60 rifles if they can pass the patrol rifle program.  Or you can spend less and by half as many rifles for the cars and take on he liability that comes with it when an officer gets out and has to use iron sights because his primary sight has failed.

The policy will reflect what they can have or can not have.  I like it better that way so they can have a weapon they can train with.

Run some optics with some high quality BUIS. Thats my answer. Having both seems like the most beneficial thing to do.

What you are looking for is a discussion on parralax error.

It should be so easy to find that I won't look for it.

The same shooter with the same zero can acheive multiple points of aim with a slight amount of head movement.

You can see it in any red dot sight when you move your head and the reticule moves with you.

Irons don't move with you - that's enough of a point.

The difference of head placement on a stock is enough to create parallax error.

The OP is stating that he thinks iron sights shoot different for each shooter. Iron sights don't have parallax error.



In fact I think iron sights are the most consistent for different shooter of all the sighting methods.



If iron sights need to be adjusted for each shooter I have to wonder how did people get by with all of those guns made with fixed iron sights such as the older Colts.
 

I can see it being a valid argument on a match rifle shooting 600 yards. As emergency backup sights on a defensive rifle that needs to hit COM within 75 yards, I don't see the cost/benefit equation to justify 2x the cost.

The effect of shooter's having different zeros is not just an iron sight problem; it goes for scopes and red dots as well.  Just the different mass distribution of the shooters will have an effect on how the rifle recoils, thus change the point of impact.  Couple this with different tensions in hold, head placement, etc. and you get a whole host of things that change where the barrel is pointed when the bullet leaves.

A rifle when fired is a dynamically moving object with all kinds of vibrations.  There are many factors that can easily change how the rifle moves in terms of both recoil and vibrations.  The individual shooter is just the most significant variable.  The effect of a zero change also  can show up when the same shooter changes position.

In short, no rifle can be sighted in by one person and expect to have the same point of impact across a whole host of shooters.  Most of the hunters on this site laugh and post this whenever they read about someone going to a gunsmith to have their rifle sighted in for them.  They know that only you can  properly sight-in your own rifle.

I got a ruler and took measurements on an M4 on the rifle rack in the office. (I work at a Joint command, but I think it was an Army-issued weapon.)  The rifle has a Matech BUIS mounted on the rearmost slot.  The sight radius is 370mm, and the aperture on the Matech is 2mm in diameter.  Assuming people can pick up the center of the front sight reliably, the math would put the maximum spread of the different aiming lines through the rear aperture at about 18.6 MOA.  In practice, it would probably be somewhat smaller, due to that natural tendency for your eye to look for the center of the hole.  That seems consistent with the observations of deviations in a 6 in radius at 50 yds.


On the other hand, FM 3-22.9 states:
5-40. When standard zeroing procedures are followed, a properly zeroed weapon for one Soldier is close to the zero for another Soldier. When a straight line is drawn from the target's center to the tip of the front sightpost and through the center of the rear aperture, it makes little difference whose eye is looking along this line. There are many subtle factors that result in differences among individual zeros. Instructors/trainers should emphasize the similarity of individual zeros instead of the differences.

5-41. Most firers can fire with the same zeroed weapon if they properly apply marksmanship fundamentals. This information can be useful in three ways:
(1) If a Soldier has difficulty zeroing and the problem cannot be diagnosed, a good firer could zero the weapon to find the problem and eliminate the weapon as part of the problem.
(2) When a Soldier must fire another Soldier’s weapon without opportunity to verify the zero by firing for example, picking up another man’s weapon on the battlefield), the weapon will be closer to actual zero if the sights are left unchanged. This information is useful in deciding initial sight settings and recording zeros.
(3) All weapons in the arms room, even those not assigned, should have been previously zeroed by the last Soldier they were assigned to. Zeroing this newly assigned weapon should start with the sights left where they are.

(I should point out that when I have gone through combat training, they always had us start from mechanical zero, instead of where the sights were last set.)


I would recommend doing some testing with realistic scenarios (that reflect likely situations where the rifles would be employed) to check how much of a loss of accuracy is experienced when a bunch of different people use the same weapons.

First, let me apologize for misunderstanding the original post, and thank Proconsul for clarifying the question. I'm going to agree with what several posters have said: it's not so much the sight system that causes different points of impact for different shooters. It can and will happen with optics as well as iron sights. People have mentioned body mass, how the weapon is held, cheek weld, and so on. All these affect point of impact more than minor differences in in interpreting sight alignment or sight picture. And no one has yet mentioned the most important factor of all: trigger control. If one shooter is pulling more aggressively than another, or worse, jerking the trigger, there's going to be a big difference in group size and point of impact. You can pull a shot left or right with the trigger also.

I think that, if you can get everyone well trained in shooting fundamentals, especially trigger control, the differences in point of impact from shooter to shooter due to sights will not be enough to be a real factor in a SHTF situation where no one is shooting target accuracy anyway.

If shooting fundamentals are followed, once the iron sights are set and the same POA was taken,  shouldn't the POI be the same for every shooter?  

There is only one way to line up the sights, any change in POI should be due to different POA or shooter error.  Why not train the officers to use proper fundamental marksmanship?  

If not, you now have 60 rifles with 60 possible different POA/POI.  Should something happen that an officer needed to use another officers weapon, the borrowing officer may now pose a liability for public safety because of errant rounds fired.

ETA - Isn't an RDS' parallax largely negligible?  Again, wouldn't proper shooting fundamentals equate to the same POA/POI for each shooter?