Vision & sight blade width

[LPatterson]

This is a great thread, I just my sights changed to a .09 front & .125 rear and went from middle of the pack to 3rd in division. I could have been 1st if it weren't for a noshoot on a transition trying to move before I broke the shot.

[aXXman]

For focusing on the front sight, I wonder if the smallest ghost ring/aperture rear might help.  I suggest this because when you switch apertures on an AR, the front sight post and/or a red dot will always look sharper and more in focus when you use the smaller aperture.

<{POST_SNAPBACK}>

The reason you see the front sight clearer is due to a pinhole effect that happens and corrects blurriness because of some wierd physics thing. Back when I was a kid and didn't want to wear my glasses, I could actually see decently by looking through the hair in front of my eyes at the chalkboard or whatever if I did it just right.

[Flexmoney]

I wanted to bump this thread up, as the topic has been brought up recently in other threads.

[DRAGONSLAYER]

Im running a .1 front and a .110 rear for .9 ratio.

The light bars on either side are very small and i cant get a sharp front sight focus.

My accuracy suffers severly when i speed up past 10 yards is ok if i slow down but obviously its costing me time.

I dont understand how you get the perceived ration calculation.

Any recomendations.

[bkeeler]

Im running a .1 front and a .110 rear for .9 ratio.

The light bars on either side are very small and i cant get a sharp front sight focus.

My accuracy suffers severly when i speed up past 10 yards is ok if i slow down but obviously its costing me time.

I dont understand how you get the perceived ration calculation.

Any recomendations.

Try a .125 rear and a .110 front. I like a .015 difference between the front and rear.

BK

[socman777]

Sight Coverage of Target

Here is a useful formula I found that will give you a close approximation of target coverage by the front sight. The following are based on two stock Glocks, the G26 and G34 (the 34, of course, has the longer FS distance. Not relevent, but as an additional factoid the stock rear sight on these Glocks is close to 0.125. The stock front is about 0.140. Glocks are sighted in by factory for a dead-on hold at 25 yards. Currently the factory also sets the rear sight ("...a few thousandths to the right") on the basis that they believe most right-handed shooters tend to shoot a tad left.

Formula: W/(D x .0003) = C

W = width of front sight in inches

D = distance of sight from eyes in inches

C = coverage of target by sight in inches at 100 yards

For G-26 (std 0.140 front sight):

Sight distance = 23.5 inches

Coverage:

At 25 yards = 5 inches

At 15 yards = 3 inches

At 10 yards = 2 inches

At 50 yards = 10 inches (9.93)

For G-34 (std 0.140 front sight):

Sight distance = 24.75 inches

Coverage:

At 25 yards = 4.7 inches

At 15 yards = 2.8 inches

At 10 yards = 1.9 inches

At 50 yards = 9.4 inches

To get the target coverage for your front sight, simply multiply the above outcomes times (your sight width/0.140).

****************

As an aside, there are a number of confounding variables:

1. actual front sight and rear sight widths, sometimes expressed as a ratio

2. actual light space, which seems to be (rear width - front width)/2. This is misleading as the both the sight radii to the front and/or rear sights and sight radius for different shooters are quite variable. This calculation may be grossly comparative between different sight combinations, but not much more.

3. perceived light space in actual useage. This solves all the issues raised above, and is Brian's observation and recommendation. He advises that a "perceived" light space of about 1/2 of the width of the front sight, on each side of the front sight "is about right".

Please note though that the target coverages listed above are actual. And perceived, lol...

Edited August 7, 2009 by socman777

[socman777]

As some know, I developed a spreadsheet that was designed to calculate Brian's ideal front sight width based on the notion that he believes a sight picture based on a "perceived" light bar of 50% of FS width, on each side of the FS.

If anyone is interested, please PM me with your email and I'll be happy to send it to you. Meanwhile I thought an analysis of some of the fine shooter here, including Brian would be revealing....

**************

Brian: "... To nutshell it, you'd like to see, at minimum, a "perceived" (not measured) one-half of the front site's width on each side of the blade. (For my arm's length, my current .115 front and .135 rear is real close..."

Me - the spreadsheet calculated Brian's ideal at 40% each side.

Tdean: "...I took about .015" off my Dawson fiber-optic front post. It's now at .120" with the rear Bo-Mar notch at .138". The "light bars" on either side of the front post are perfect (1/2 the thickness of the post) at my arms length.."

Me - No, not half, actually this works out to 38% each side.

Munitor: "...The Russians found that a front sight that was the same or slightly wider than the apparent width of the bullseye gives the best accuracy with the least eye fatigue, but because Olympic pistol targets have a wide bullseye, they found that rule impractical to implement for pistols. Instead, they settled on a front sight, 0.125-0.145 wide, which their experience has shown to give maximum accuracy and minimum eye fatigue..."

Me - this does not discuss the apparent width of the rear opening...

Munitor: "... You described your previous sight setup as .090/.112, which is a calculated 0.80 and approximately a visual 0.46 (or 2.2:1 if we use the apparent rear to front ratio like the Russians do). That gives you a bit more than half a front blade's width on each side..."

Me - actually it's more than a bit LESS than half, specifically 43% on each side.

Joe: "... I widened the factory fixed 3-dot rear notch on my Commander from .125 to .150, keeping the front at .125. This has given me a very fast sight alignment. I did the rear notch because it was the easiest to modify..."

Me - this gets a bar width of 41%.

T-Dean: "...I'm using a .075" front and a standard .110" rear notch. That puts me at .68 ratio. Pretty low by most standards it seems, but I love it..."

Me - this is truly one-half, at 51%.

Rhino: "... You guys are the first group I've seen that narrow the front specifically to get more light on either side. The reason I narrow the front sight is so it won't obscure as much of the target at 25 anf 50 yards..."

And...

Loves2shoot: "... I got convinced to go to a wider front sight last year and I (for whatever reason) pick it up faster, I still have a thin sight on my single stack and it works fine but I shoot tighter groups with the wider FS."

Me - Hmmm. Rhino goes narrower to expose more target, Loves goes wider to pick up the sight faster. And in another thread, Flex pointed out to me that the front sight needs to be your first choice, and only then, the rear sight to get the light bars you want. My spreadsheet is bisexual - solves for ideal front (based on rear) and the reverse.

Kevin Kline: "... When I was working my way up and made GM in Limited and shooting my best, I was shooting my STI with a .070 front and standard .110 (I believe) rear Bomar. I loved it and felt very fast with it..."

Me - 54%.

LPatterson: "... This is a great thread, I just my sights changed to a .09 front & .125 rear and went from middle of the pack to 3rd in division..."

Me - 49%.

Dragonslayer: [/qu"... Im running a .1 front and a .110 rear for .9 ratio.

The light bars on either side are very small and i cant get a sharp front sight focus..."

Me - 35%

BKeeler: To Dragonslayer (.1/.110), "... Try a .125 rear and a .110 front. I like a .015 difference between the front and rear."

Me - 37%. BK's advice really wouldn't change Dragonslayer's ratio much at all (35%). This shows the need for the spreadsheet.

****************

Summary

Here's the conclusions I draw:

1. Brian's ideal of "about one half", based on his own sights is actually about 40%.

2. The use of the Russian and other "sight ratios", eg. 2.2 to 1, are not particularly accurate. They imply a 50% ratio, but are actually less (closer to Brian's actual 40%).

3. There is a case to be made for choosing your front sight first - based on target coverage, or visibility, or whatever - then finding (or modifying) a rear sight to produce your desired light bars.

4. The most popular sight picture among experienced shooter posting here, not least for Brian himself, is about 40% (which I guess is "roughly half"). But it is NOT half.

Do keep in mind that my comparisons were based on an average 7.5 sight spread, and a FS radius of about 26 inches. I also found that, within reason, the FS radius was not particularly critical. Accordingly, this analysis is fair.

Enjoy...

[GlockerJeff]

I am at the point where I have to wear reading glasses to see the dot on the front site (Glock 17). It has been suggested that I go to the Sevigney sights which have a narrow front blade with light around it which would help on the distant targets. At this point I know I can pick up on that front white dot and can get on it fast. I shoot GSSF and NRA Action Pistol and can understand the benifit of seeing around the front sight but I am concerned that I may not be able to pick it up as fast as using a white dot so I have not ordered new sights. Any comments?

[alellis]

Guys

I found this thread today while researching about sight pictures etc.

On my 625 the front sight is 0.16 wide and the rear notch is 0.15.

In practice this means for me, I can just see the smallest amount of light on either side of the front post at arms length.

I think the simplest solution for me is to replace the front sight with a narrower one.

I don't want to start in with a file.

I have searched Brownells but can only find similar or larger fronts.

I am thinking maybe a .10 would be good.

al

[ebg3]

This is an interesting thread. For several years, I shot a .09 front sight(FO) and a .115 notch rear and got along great. I went to Open for a bit and when I came back to Limited, the front sight seemed way too narrow. I put in a .125 front(FO) and really liked it. I had a lot more confidence making tough shots and seemed to shoot groups better. I've since switched guns and am using a .110 front(FO) and a Bomar .110 rear and this seems to be working well. It seems to me, you can get away with using a wider front sight if you use a FO sight. Opinions?

[benos]

This post from the Fiber Optic to Irons thread probably fits better in this thread:

Talking about sight widths with numbers - the width of the vertical light bars (on each side of the front sight) will be different for people with different length arms.

What I settled in on, especially as my eyes (not me) got older, was a front to rear sight width ratio that made the sum of the 2 light bars equal the width of the front sight. That setup is quick to acquire and easy to very accurately align. (That was around .115 - .120 for the front sight width.)

On rear sight notch depth, I used to fool around with deepening a Bomar a little, but eventually got tired of ruining sights. And then if I did happen to get one filed down perfectly, a bit deeper, then I get used to that so then I'd want all my current and future guns/sights like that. So eventually I gave up messing with notch depth altogether, and just shot the Bomars, and later Wilson's sights, the way they came.

(But if you are good with a file and you have the right one, it's not to difficult to widen a factory sight a bit without ruining it.)

On front sight height, the most important thing is that when the sights are aligned, there is not any slide visible in the bottom of the notch. I liked my front sight to be just tall enough so that, as the front sight's coming down into the notch, just as the slide disappears from the notch the front blade is level with the top of the notch.

Although I couldn't visually confirm/prove it, I always felt that relationship helped me "park the front sight" more expeditiously.

be

[oldtrooper]

This is something to try that is not a permanent alteration. It has worked for me "older eyes" in NRA Action Pistol in the metallic division. I was using a fiber optic on an STI six inch a couple of years ago and when the light was at certain angle it made the FO brighter and actually made it more difficult to center the front sight in the rear notch. This front sight was the type that had the hole all the way through the front sight. I cut the fiber optic out and left the hole open.

It works great on NRA Action Pistol especially with the newer black X-ring and on the plates. If you get the sights on target with the brown paper target and the black X-ring you will see black in the empty FO hole while aligning the front sight if it's on the X-ring. When shooting the white plates you can concentrate on the front sight and still confirm that you are on the plate if the empty FO hole is white.

The best thing is that you can put the FO back in easily if it dosen't work for you.

[ck1]

Something to take into account is that different length guns need different sight specs to arrive at the same front blade-to-light bar ratio...

A front sight will seem thinner the further away it is from your eye, so a .125 front on a 5" gun is a lot different than a .125 on 4" gun... And playing with rear notch width, the same thing applies, a longer gun can wear a tighter rear notch and seem as "open" as a shorter gun with a wide rear notch...

Just thought I'd mention this since these different sight numbers being thrown around all are tied to the length of gun and length of sight radius they're being used on. For example, the same sights that kick ass on a longer pistol like a G34 or a 1911 may feel "closed in" on a G17 or a Commander...

[socman777]

Just thought I'd mention this since these different sight numbers being thrown around all are tied to the length of gun and length of sight radius they're being used on. For example, the same sights that kick ass on a longer pistol like a G34 or a 1911 may feel "closed in" on a G17 or a Commander...

That is exactly why I developed my sight spreadsheet, as it takes into account sight radius from your eye, allows you to plug in your current or proposed combination. It will return the lightbar percent of the named combination, will also return ideal front for the rear named, and ideal rear for the front named. I am happy to sent the spreadsheet to anyone, just PM me and give me your email (as the file is a spreadsheet file, can't be PM'd).

[cletus9mm]

looking at the numbers i think i'm on one of the extreme ends of this spectrum. i'm 5'9" and my favorite sights out of the pistols i own and shoot are the sights on my cz tactical sport. the gap on my rear sight measures .167 and my front sight measures .095 at the top. the first time i looked down the sights i was very nervous that i would never like it or get used to it. my first time sighting the gun in i was pleasantly surprised. my groups were some of the best i had ever shot. like others here have mentioned your eyes naturally line things up, and these sights are no different. i might add that friends of mine all had the same perception about the sights. they all said something along the lines of "the rear sight is so big and the front is so narrow". they were all skeptical and when they put it on paper, they changed their minds. my suggestion, get the rear sight as wide as you can and the front sight as small as you can. if you don't like it, make the front bigger! good luck!

[redbird1976]

I think I've now read all the posts dealing with vision, focusing on the target, front sight, in between, changing 'vision' to suit situation, etc.

But no mention of the affect of the front sight blade WIDTH WRT how much 'white space' you see in the rear sight notch.

I started aiming at the wall while cogitating the things I read, and I just realized that my sights have very little white space, which makes it very very hard to pick up the front sight quickly (given my previously mentioned problems).

I think that if my index was perfect, I could just use the rear notch alone.  Might shooot high or low, but the lateral alignment would be there.  Wish I had a sight tool; I could try installing a narrower blade.  This Kimber has a dovetailed front sight... Do they make different widths for it?

I also noted that the serrations on the front sight are only visible when a strong light comes from a particular angle & direction.  So they are not a reliable way to gain a focus on the blade.

The crummy lighting on the indoor range is a worst case scenario too.  But it ought to force me to index!

Dawson Precision makes a nice fiber optic front sight for the Kimber. I used a .100" wide front sight on my .45 and .40. They gave me a little more light on either side without compromising the precision.

[redbird1976]

looking at the numbers i think i'm on one of the extreme ends of this spectrum. i'm 5'9" and my favorite sights out of the pistols i own and shoot are the sights on my cz tactical sport. the gap on my rear sight measures .167 and my front sight measures .095 at the top. the first time i looked down the sights i was very nervous that i would never like it or get used to it. my first time sighting the gun in i was pleasantly surprised. my groups were some of the best i had ever shot. like others here have mentioned your eyes naturally line things up, and these sights are no different. i might add that friends of mine all had the same perception about the sights. they all said something along the lines of "the rear sight is so big and the front is so narrow". they were all skeptical and when they put it on paper, they changed their minds. my suggestion, get the rear sight as wide as you can and the front sight as small as you can. if you don't like it, make the front bigger! good luck!

I concur. I love the sights on my TS. They are very easy to shoot.