confusion about moving sights [Archive]

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corvette8n

11-12-2007, 06:23 PM

nitroproof

11-12-2007, 06:28 PM

Rear sight... move in direction you want bullet to move.

Front sight, the opposite direction. :bigsmyl2:

Trial and error is what I use...

Tom Myers

11-12-2007, 07:17 PM

Corvette,

The amount of movement for either the front or rear sight is determined by the ratio of the sight radius to the distance from the front sight to the target.

Let T = the distance, in inches, from the front sight to the target.
Let R = the distance, in inches, from the front sight to the rear sight.
Let I = the distance, in inches, to move the point of impact .
Let S = the distance, in inches, to move either the front or rear sight.
Now - to determine S, divide R by T and multiply times I.

S = R / T * I

For the sake of demonstration let us say that the distance from the front sight to the rear sight on the Puma is 16 inches and the target is at 50 yards ( 50 x 3 x 12 = 1800 inches).

Divide 16 by 1800 to get 0.00888888.

Now multiply 0.00888888 times 2 inches to get 0.01777.

You would need to move the rear sight 0.018 inches to the left or the front sight 0.018 inches to the right.

You can figure out R/T at home and make the initial adjustment at home then take a calculator and micrometer to the range with you to make the final adjustments.

Hope this helps.
Tom Myers
Precision Ballistics and Records (http://www.tmtpages.com)

Took two iron sighted rifles to the range today.
6.5 Carcano is shooting about 6 inches to the left of the bull.
A .45 Colt Puma and it is shooting about 2 inches right.
On the Puma I can move front or rear sights.

The Carcano has a fixed rear so I can only move front.

A chart would be helpful that I could print and take with me to the range.
:Fire:

Char-Gar

11-12-2007, 08:30 PM

Man... I would give up shooting if I had to do that much math. I hate, loath, dispise and abominate math in any form.

Tom Myers

11-12-2007, 08:51 PM

Chargar,
It realy isn't all that much math. I just used a lot of words to say:

Sight Radius / Range X Bullet Strike = Adjustment

Tom Myers

Man... I would give up shooting if I had to do that much math. I hate, loath, dispise and abominate math in any form.

Mk42gunner

11-12-2007, 09:00 PM

FORS- Front Opposite, Rear Same.

Move the front sight the opposite way you want the bullet to move. Rear sight moves the same dirrection bullet impact does.

Personally, I like nylon drifts for sights as opposed to brass.

Robert

Char-Gar

11-12-2007, 11:46 PM

Tom.... Any math is too much math! It is all the Devil's work!

Frank46

11-13-2007, 12:31 AM

Tom.... Any math is too much math! It is all the Devil's work!

I remember my high school teacher saying that algebra would come in handy. Well
the closest I came to higher math was a modified greenhil formula. Other than that, at age 61 math gives me a headache. Frank

Morgan Astorbilt

11-13-2007, 12:38 AM

It's nice shooting my buffalo rifle with 36" between the sights. At 100yds., The bullet impact changes 100x the sight change. With a vernier tang sight, that's almost math free. Haven't had to take off my shoes yet, my fingers being enough!:mrgreen::mrgreen::mrgreen:
Morgan

Char-Gar

11-13-2007, 08:24 PM

MT Gianni

11-13-2007, 08:53 PM

10 yrs ago, as his 8th grade project I answered the neighbor kids survey on math. My response was that as a pipefitter the difference in working 32-35 weeks a year and 50-52 weeks a year is math skills. Gianni

Blammer

11-13-2007, 09:04 PM

bring lots of ammo!

wills

11-13-2007, 09:30 PM

Fortunately I cant do math, otherwise I might have become an engineer!

charger 1

11-14-2007, 09:43 PM

F.A.R.T.
F.RONT A.WAY from where you wanta go
R.EAR T.OWARD where you wanta go

hydraulic

11-14-2007, 10:17 PM

I'm so poor at math I have to take my pants off to count to 21.

joeb33050

11-15-2007, 07:58 AM

He Asked For A Chart-here's A Chart. It Won't Print Here For Some Complex Computerese Reason. It Also Won't Upload Because The .doc File Is Too Big, And It Won't Upload The .xls File Because This Kluge Doesn't Speak .xls.
Anyone Who Wants To See The File And Help Get It Into Shape Just Send Your Address And I'll E-mail Either Or Both Files. Why Is This Thing Printing In Upper Case? I Do Love The Computer.
Joe B.

jawjaboy

11-15-2007, 08:02 AM

I'm so poor at math I have to take my pants off to count to 21.

[smilie=l:

First time I heard that one!

joeb33050

11-15-2007, 08:31 AM

Frank... My High School Math teacher told the same lie. I am 65 years old, hold bachelors, masters and doctors degrees and have yet to find a need beyond addition, subtraction and multiplication.

It is the Devils work I tell you!

Do you think that if you lived somewhere other than So Texas that the math might come in handy? There's a lot of folk in MA and CA who use a little math almost every day at work. I bet I spent 10% of my working life helping folks do arithmetic or doing it myself.
Remember, if it weren't for the math there wouldn't be any insurance companies, no lotteries, derivitives would never have been invented, there'd be no arbitrageurs and 92% of the people employed in investment banking and the markets would be unemployed. No Enron, no Tyco, no Worldcom, no CEOs making the GDP of Uruguay. Wait a minuite...........
joe b.

Morgan Astorbilt

11-15-2007, 08:44 AM

And best of all, NO LAWYERS making 30-50% fees!
Morgan

NVcurmudgeon

11-15-2007, 08:55 AM

Took two iron sighted rifles to the range today.
6.5 Carcano is shooting about 6 inches to the left of the bull.
A .45 Colt Puma and it is shooting about 2 inches right.
On the Puma I can move front or rear sights.

The Carcano has a fixed rear so I can only move front.

A chart would be helpful that I could print and take with me to the range.
:Fire:

Here you go. www.lymanproducts.com/lymanproducts/images/sight%20

You will go to a Lyman No. 57 sight page. Scroll down until a sight correction chart appears. No math, just look it up on the chart.

NVcurmudgeon

11-15-2007, 08:59 AM

Looks like the URL was too long to print entirely. After the part where it says lyman products.com the rest is /lymanproducts/images/sight%20

Tom Myers

11-15-2007, 10:07 AM

joeb33050

11-15-2007, 02:03 PM

Lyman's Charts are in PDF file images. I made a composite of them and loaded it to my website.

Hope this helps.

Tom Myers

Precision Ballistics and Records (http://www.tmtpages.com)

http://www.tmtpages.com/LinkSkyImages/forum_images/Rear_Sight_Correction.gif

My chart is far easier to understand and much better looking than this one. Nicer in every way, and neater. Beautifully composed, a triumph of the workbooker's art, a joy to behold. Having a copy of my chart may cause slight weight loss, more muscle mass and hair regrowth. I just can't figure out how to put it on this forum. Perhaps one of you computer wizards might put it up for me. pm me for the files, .doc or .exe. Keep in mind that my birthday is !/!/08, and presents are entirely appropriate. pm me for the address. No flowers or pets of any kind!!!
joe b.

oneokie

11-15-2007, 07:06 PM

Front opposite, Rear same is too simple.[smilie=1:

Lets make it more complicated:

Move the front sight toward the point of impact

Rear sight away from the point of impact.

Couldn't resist, the devil made me do it:coffee:

montana_charlie

11-15-2007, 07:30 PM

Perhaps one of you computer wizards might put it up for me.
From the way you describe your chart, I feel I must have it...if only for health reasons. Try this...

Create a compressed (zipped) folder on your Desktop and drag a copy of your chart into that folder. It will take on a filename that ends with .zip.

Try uploading that file to the forum.
CM

joeb33050

11-16-2007, 08:38 AM

Create a compressed (zipped) folder on your Desktop and drag a copy of your chart into that folder. It will take on a filename that ends with .zip.

Try uploading that file to the forum.
CM

CM;
I don't think that this is funny, it is not kind to mock the elderly. Just because I don't know what or how a (zipped) file is, and can't drag much of anything an more is no reflection on my excel abilities. I've lookied all over the top of the desk, it must have fell off.
I'm sending both to Tom.
joe b.

Tom Myers

11-16-2007, 09:48 AM

Joe,

I just set the file on top of my desktop,, zapped it with my zipper, hooked a chain on it, drug it over here to the forum and stored it in my bin.

Click on the Attached File link at the bottom of this post to open the file in Microsoft Word format.

Tom Myers
Precision Ballistics and Records (http://www.tmtpages.com)

Tom Myers

11-16-2007, 09:58 AM

Here is another way to do it.
I saved the word document as an HTML file, uploaded it to my website and then linked to it from this post.

Tom Myers

Joe Brennan's Sight Setting Chart (http://www.tmtpages.com/LinkSkyImages/forum_images/SIGHT%20SETTING%20CHART.htm)

4060MAY

11-16-2007, 10:10 AM

just hit it with a hammer, size depending on caliber, until it shoots where you want it to.

44man

11-16-2007, 10:43 AM

You guys are just too funny! :mrgreen:
Tell me how to measure the movement of a front sight in a dovetail on a round barrel after knocking it over with a punch and hammer!!!!!!!!!!!! [smilie=1:
Seems as if trial and error is the only way.

montana_charlie

11-16-2007, 01:15 PM

You guys are just too funny!
I've been smiling, too, 44man.
The original poster seems to have two front sights that can be moved in their dovetails, and a rear that is (perhaps) click-adjustable.

How one gets a movement of .004" (for a 16" sight spacing) is beyond me. I can get a similar effect by only wipng the dust off of one side of the blade.
CM

Tom Myers

11-16-2007, 01:21 PM

It is a little tricky, but I use a dial micrometer and a small, square shafted screwdriver. But any small, parallel sided object that can be placed against the sight to hold one of the micrometer jaws away from the opposite side of the barrel will work.

Place the barrel in a vice and angled down to rest the end on bench top or a block of some sort

Positioning the micrometer jaws over the barrel with the tips resting on the bench top will maintain the vertical alignment.

Measure and record the distance from the barrel side to the block positioned against the sight.

Drift the sight over then set up, take another reading and then subtract the distance from the first reading.

Repeat the process until the sight has been moved the desired distance to eliminate the sighting error.

If I measure very carefully, this will usually put the bullet impact spot on.

Tom Myers
Precision Ballistics and Records (http://www.tmtpages.com)

joeb33050

11-16-2007, 01:43 PM

How one gets a movement of .004" (for a 16" sight spacing) is beyond me. I can get a similar effect by only wipng the dust off of one side of the blade.
CM
If I did the arithmetic right. that .004" is the truth. Now you may not like the truth, and you maybe can't stand the truth, but it is the truth.
From the book:
Most Lyman 48, 66 and 57 , Redfield and Parker-Hale PH 7A sights have one click equal to .002 inch, one click moves the rear sight .002 inch. If there were 1 yard = 36 inches between the front and rear sights, then moving the rear sight .002 inch would move the point of impact of the bullet one hundred times as far at 100 yards, or .2 inch. The Lyman 57 rear sight in the picture has an elevation scale marked in 3 minute divisions. One rotation of the knob has 12 clicks and moves the slide one division of 3 minutes.

The distance between sights determines how much one click of .002 inch moves the point of impact of the bullet.
Distance Between Sights Bullet Moves At 100 Yards 36" .200 inch
30" .240 inch
28" .256 inch
24" .300 inch
18" .400 inch
I thought he wanted a chart.
joe b. (Are you guys feeling the hair coming back?)

Tom Myers

11-16-2007, 01:50 PM

I think that Charlie was wondering just how one could make an adjustment as small as 0.004" when drifting a front or rear sight.
It ain't easy. Usually I just drift the sight back and forth and measure each time until I finally get the reading that I want. It seems easier for me to do it at a workbench rather than the shooting bench. Of course I don't get in as much shooting as if I were to make the adjustment by trial and error.

Tom Myers