Why have the rear sight as far from the front as possible?

Canadiankeeper

Canadiankeeper

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With my recent jump into the black and green rifle club. I have come across my first set of iron sights that I can place them where I like. I happen to notice everyone has their rear as far back as possible. That seems off to me because its such a large rear sight aperture so close to your head that it goes very out of focus and you don't seem to be able to center the front as well or as easily. It seemed easier to move the rear up a bit so that you would be able to tell if the front was center in the rear this giving you better consistency... One IE me would think ?I haven't spent all most all my shooting career behind fixed pistol sights, shotgun bead sights and optics. If any one can help me out on this, explain why and what the benefits are I would love it.

Flame suit on. :HR::cool:
 
The greater the distance between sights, the longer the sight radius which allows more accuracy. Obviously there are practical limitations to the placement of the sights. The down side to the sights being further apart is that the ability to find your target and line up your sights is slower than having them closer together. Phil.
 
I also find that added to the benefit of the longer sight radius, when I look through the rear sight with it close to my eye it almost entirely disappears but my eye still picks up enough of it to allow me to center the front post. When I want precision I flip to the little aperture. I think I read somewhere that the large aperture is for 0-200 yard moving targets and allows a greater field of view.

I pretty much never use the flip ups anymore. I zero them when I install them and leave them folded after that. A good optic is much better for me.
 
If the aperture is really that large, its meant for raw speed, not precision accuracy anyway. I'd flip it to the small hole, or change it to the smallest available aperture and maintain a long sight radius.
 
Canadiankeeper said:
That seems off to me because its such a large rear sight aperture so close to your head that it goes very out of focus and you don't seem to be able to center the front as well or as easily.
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Ghost ring sight. The rear sight is supposed to be out of focus, the eye natural centers the front sight in this.

It's not a old .22 sight, where you're trying to focus on three different distances and trying to line everything up perfectly.
 
Rear apertures work because your eye is naturally drawn to the brightest part of the sight, the middle of the aperture. A smaller aperture will have a smaller bright spot so the margins for error is smaller (I think)

The farther the rest and front sight are apart, the longer the sight radius and thus it is easier to keep aiming errors small. A little bit off with a large sight radius means less deviation (angular) of the gun from the intended point of aim
With a short sight radius, a small error is reflected in the barrel being moved a greater angle off the intended point of aim.
 
cr5 said:
I also find that added to the benefit of the longer sight radius, when I look through the rear sight with it close to my eye it almost entirely disappears but my eye still picks up enough of it to allow me to center the front post. When I want precision I flip to the little aperture. I think I read somewhere that the large aperture is for 0-200 yard moving targets and allows a greater field of view.

I pretty much never use the flip ups anymore. I zero them when I install them and leave them folded after that. A good optic is much better for me.
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mine is only one aperture on rear sight, its seems like it is more of a combat quick shooting type sights then making groups.
 
Bolivar said:
Rear apertures work because your eye is naturally drawn to the brightest part of the sight, the middle of the aperture. A smaller aperture will have a smaller bright spot so the margins for error is smaller (I think)

The farther the rest and front sight are apart, the longer the sight radius and thus it is easier to keep aiming errors small. A little bit off with a large sight radius means less deviation (angular) of the gun from the intended point of aim
With a short sight radius, a small error is reflected in the barrel being moved a greater angle off the intended point of aim.
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so it sounds like if I rocked it up farther it would point out errors ? I moved it up and that is when the groups got tighter and the shooting more accurate. Seems more for quick shots not accuracy.
 
Marksmanship has more to do with comfort than orthodox practices. I have shot with very long eye-relief, with a back up sight at the front of a flat top rail (forward of the optical sight, as if it were removed from the rail in the event of a failure). It was effective enough, but I didn't find it superior to the conventional placement. As long as you can achieve a good cheek weld, the difference at ranges relevant to iron sight shooting were negligible for me.
 
Canadiankeeper said:
mine is only one aperture on rear sight, its seems like it is more of a combat quick shooting type sights then making groups.
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Probably the case. You didn't say what sight you are working with specifically but most iron sights on ARs now, that can be moved around are "back up" sights. That is, there are there as a back up in the event your primary optic goes down (breaks, dead battery etc). They are not intended to be as accurate as iron sights that are intended to be the primary sight, like on a carry handle. A large rear aperture is intended to be quick to sight through and useful in low light where a smaller aperture will be a bit slower and reduce the light getting to your eye making it hard to use in low light.

Canadiankeeper said:
so it sounds like if I rocked it up farther it would point out errors ? I moved it up and that is when the groups got tighter and the shooting more accurate. Seems more for quick shots not accuracy.
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I think what you are likely experiencing is the rear aperture appearing smaller as you move it forward, thus reducing the size of the bright spot at the center that your eye is drawn too. You would probably have the same effect if you had a sight with a smaller aperture, mounted at the rear of the receiver.

I think Jube said it pretty good above. Basically if your rear sight placement somewhat forward of the rear end of receiver works for you, go with it. That being said, can you leave the sight there and still place a primary optics sight (red dot, scope etc) on the gun? If so, cool.

If irons are going to be your primary sighting system, I would suggest going with something fix (not folding), with elevation and windage adjustment and a smaller rear aperture so you can move the sight to the rear and increase your sight radius. I think that would pay off for you in the long run.....but it's your rifle and your money. It's up to you to decide what is best for you.
 
Bolivar said:
Probably the case. You didn't say what sight you are working with specifically but most iron sights on ARs now, that can be moved around are "back up" sights. That is, there are there as a back up in the event your primary optic goes down (breaks, dead battery etc). They are not intended to be as accurate as iron sights that are intended to be the primary sight, like on a carry handle. A large rear aperture is intended to be quick to sight through and useful in low light where a smaller aperture will be a bit slower and reduce the light getting to your eye making it hard to use in low light.



I think what you are likely experiencing is the rear aperture appearing smaller as you move it forward, thus reducing the size of the bright spot at the center that your eye is drawn too. You would probably have the same effect if you had a sight with a smaller aperture, mounted at the rear of the receiver.

I think Jube said it pretty good above. Basically if your rear sight placement somewhat forward of the rear end of receiver works for you, go with it. That being said, can you leave the sight there and still place a primary optics sight (red dot, scope etc) on the gun? If so, cool.

If irons are going to be your primary sighting system, I would suggest going with something fix (not folding), with elevation and windage adjustment and a smaller rear aperture so you can move the sight to the rear and increase your sight radius. I think that would pay off for you in the long run.....but it's your rifle and your money. It's up to you to decide what is best for you.
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I do plan on putting an optic on, but after dropping what I did on the rifle and mags, another 1000 for a decent optic is going to take a month or two to have expendable... with out me getting chewed out or putting it on visa.

The sights im using are troy flip up battle sights, rear adjusts wind and front is elevation. They came with rifle, I guess ill just have to do with the back up battle sights as prime sights for a while lol. Ill just move them up, im not doing 3 gun or running and gunning. Mostly just target and hunting.
 
Bolivar said:
Yup, rock what ya got. What rifle did you get if you don't mind me asking. I had assumed an AR but obviously not if you plan to hunt with it.

Regardless, have fun and enjoy your new rifle.
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Yea, will just have to make do. Will try it again with the sight rear sight all the way back. Will most likely get frustrated and move it forward again heh.... Anyways, love showing it off so why not..
 
Bolivar said:
Rear apertures work because your eye is naturally drawn to the brightest part of the sight, the middle of the aperture. A smaller aperture will have a smaller bright spot so the margins for error is smaller (I think)

The farther the rest and front sight are apart, the longer the sight radius and thus it is easier to keep aiming errors small. A little bit off with a large sight radius means less deviation (angular) of the gun from the intended point of aim
With a short sight radius, a small error is reflected in the barrel being moved a greater angle off the intended point of aim.
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^^

Like he said. Your eye will automatically center in the rear sight. Move it the back.
 
Canadiankeeper said:
where could I source a smaller aperture ?
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If memory serves with the stock MI irons on your XCR you should be able to pivot the rear aperture between a large and small ring. Notice in this picture the sight has the large aperture 'up' and the small aperture pivoted down. Press against that aperture and you should be able to pivot the small one up.

mctarers.gif
 
Yeah, but he does not have an M1 rear, check the pic.it doesn't look like there is a small aperture.

Ganderite - you know way more about this stuff than me but I think the OP is having a problem with the large size of the rear aperture up close to his eye.

Does my theory about moving the sight forward and the aperture appearing smaller, with a correspondingly smaller bright spot make sense?
 
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