HP rifle sight picture & the "bright line"

[InTheBlack]

Crap. Spend about 2 hours composing a post; then when I Submitted it the system told me I had to log in again and the whole thing disappeared into the ether.

Short version-- how do you deal with the "bright line" above the front sight on Service rifle sights? What's the "process" of seeing what you need to see? How do apertures & colors & lenses change/minimize the brightness or thickness of the "bright line?"

How sharply _can_ one see a 6" dia black (the 100 yard reduction)? When focused on the front sight, how blurry is it "supposed" to get-- how can I tell if my vision is seeing it worse than I ought to be able to see it?

What's the _process_ of getting the sight picture--
do you first focus on the black to discern how big it seems to be, and then raise the front sight to the center, then change focus to the front sight and decide if it still looks like it is centered, and go back and forth till it looks centered both ways? Or what???

 

[Swampy]

ITB,

I've been shooting since I was a kid, but just discovered NRA & CMP Highpower about 3 years ago. Before that shot mostly scoped rifles, some handguns. Now am Expert rated, bordering on Master..... Have learned a couple things, but still lots to go. Will try to help you out here.

Not sure what you mean by a "bright line"...... Never heard of it.

When shooting with irons the bull is going to be fuzzy. No way around it. It's the nature of human vision (and optics in general) that you ABSOLUTELY CANNOT focus on two objects at different distances simultaneously.

I can relate to you my own experiences....

First off, I'm 47 years old. Have had bad eyes since birth. Legally blind without specs. Normal vision is something like 20/800, correctied is 20/25 or 20/30 (my current prescription for distance is a +7.25 diopter). Fortunately, when shooting the only thing that matters is that you get a proper correction to let you see the front post clearly. All it takes is a little experimenting to find the right lens prescription.

I shoot with a Knobloch shooting specs system. This lets me put the primary lens in the exact spot I need for it to be centered on my vision path to the front sight and bull. For most people this is going to be higher and more in toward the bridge of the nose than your normal vision path.

I have two lenses that I use in the Knobloch holder. One is my normal distance prescription backed off 1/2 diopter (+6.75), the other is backed off by 3/4 diopter (+6.50). The .5 is what I use with the M1, M1-A, and similar length rifles. I use the 3/4 for the AR, K-Mausers, and other "shortys" that need the extra pull back to get focus on the front sight.

With these lenses in place I can see just fine, though if I just look off into the distance, things appear to be slightly out of focus (including the target bull). This is normal and what you want.

BTW, if you are of an age that you need reading glasses or wear bi-focals, you can benefit from a special shooting prescription too. Trying to ignore this simple fact is futile and bound to cause frustrations to those vain enough to want to "tough it out" with their normal glasses or go without glasses. Your distance vision may be "just fine" with your normal glasses or even without, but if you need "something extra" in order to read a book or newspaper, the same condition shows the NECESSITY of "something extra" to see the front post sharply.

One of my 1/2 diopter "backoffs" is ROSE tinted. This seems to help in gaining contrast on bright sunny days. It does not help much at all on hazy or foggy days. I'm thinking of getting one tinted amber or yellow for those conditions.

Re Sight Picture..... I never even attempt to focus on the bull. What's the point?? Focusing on the bull tells me nothing I don't already know. As soon as I have a view through the sights I immediately focus on the post and bring it into alignment at 6:00 on the little black fuzzy ball and take the squeeze.

How fuzzy is the bull "supposed" to be??? That's purely a function of your vision, the light conditions of that day, and the effects of whatever "enhancements" you are using, i.e. glasses, tints, apertures, etc..... The goal is to make the bull as clearly defined as possible (while maintaining primary focus on the front post), but the ability to to do this is limited by the aforementioned factors.

On a bright sunny day, with the target in full sun, your pupil will close down, enhancing your depth of focus. You will also be able to use a smaller rear aperture and maintain clarity on the target.

On a cloudy or hazy day things are not so good, ditto if the target is in the shade. Your own pupils open up to let in more light and degrade your depth of field. Less light means that you cannot use an ultra fine rear aperture without affecting your ability to see the bull "clearer" either. Less than optimum conditions means less than optimum ability to get a defined sight picture. It's still possible to shoot well (as long as the sight post is in focus), it's just not as easy as with high sunlight.

The bull is going to be blurry and fuzzy with a proper sight picture. Work with what you have at the moment. You have some control with your glasses prescription, tints, and apertures, but in the end when the Match Director calls "Ready on the Right, Ready on the Left........." it's past the point of worrying about what you can change. You gotta' work with what you got at that moment.... If the sun suddenly goes behind the clouds, that's tough (you can play the "Light's up-Sights up.... Light's down-sights down" game if you know your vision). You have to take the shot with what you got...

Don't worry about the bull. As long as you can bring the front post into sharp, clear focus, you will be able to get a consistent sight picture and alignment. That's the key issue in shooting "X's" on a regular basis.

One more thing...... PRACTICE, PRACTICE, PRACTICE.....

Best regards,
Swampy

 

[cookhj]

try sight black. either from a carbide lamp or the cheap spray on stuff. both help.

 

[InTheBlack]

I use spray black; if people think that the old fashioned carbide is much better
then I'll spend some more bucks to see if it helps.

What I see under most conditions is a bright line of light on top of the front sight.

The USAMU Service Rifle book mentions that with bright light on the target, some people see a halo around the bull; what I see under a lot of conditions is this bright horizontal line.

I'm trying to figure out why I see it in order to minimize it.

I know, for example, that light on the side of the front post washes out that side, so you tend to shoot towards the light. Or that light on one side of the the target has the opposite effect, or can cause vertical displacement because the apparent diameter of the black changes.

I need to go to the range and compare the effect with the front sight in the sun vs under the roof.

When trying to shoot 6oClock, I almost always see a "line of white" and can't tell if its this optical effect or if I'm really holding the front blade somewhat under the aiming black.

When shooting COM, the black becomes washed out or mis-shapen by this bright line.

My CMP Bushmaster has a 0.40 aperture. Thinking about getting the Bob Jones so I can change the size and maybe put in a diopter /colored lens.

I am nearsighted, but not quite enough to need bifocals. Experimenting at the computer, about 27 inches away, wihout glasses: 20 point Courier type is readable but fuzzy. 22 point becomes bold and is readable because of the better contrast, but 24 point would be better. Actually, I can read 10-12 point if I bend my face forwards a bit, but its my left eye doing the work (my left eye is better than my right--aiming--eye) .

Thru the 0.40 aperture, I can focus on the AR front sight without "strain" when wearing my glasses, but without glasses I can focus without any eye muscle tension at all. But without glasses, the aiming black is too indistinct; not enough contrast. Thinking about trying a diopter lens with enough power to make the black visible enough; but not as strong as my prescription. Then shoot without prescription lenses on my face.

Going to the Opthalmologist next Thur for my regular 2 year exam & new glasses, but he's not a shooter & doesn't really understand what I might be looking for in a specialty item.

The front blade is wider than the 100 yard reduction black (6") and I think I want to get a narrower blade

And when I tried to post this, it said I needed to log in again.

 

[cookhj]

i prefer the carbide lamps. the soot is corrosive, so make sure you clean your rifle after a match. get a thinner front sight too. that "line of white" is more of an optical thing. it's always going to be there; except for dark cloudy days. i use a 6 o'clock hold and i would inch the front sight up towards the bottom of the black. when the "white" just started to get into the bottom of the black, i would hold it there and squeeze. as long as you're consistant, it doesn't matter where you hold your front sight on the target.

 

[Swampy]

cookhj wrote:

as long as you're consistant, it doesn't matter where you hold your front sight on the target.

BINGO !!!!

InTheBlack, please take note......

Best regards,
Swampy