S&W revolver sights

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BillBro

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What is the value of the clicks on s&w rear revolver sights and at what distance? Do they differ by caliber? If rhwy do Im curious about 357's and 44's. Do they differ by narrel length too? If thats the vase then this could be a can of worms couldnt it?
Since the revolvers I own all fit into this age catagory, '1981 to present I of course am asking about these specifically.
 
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There are way to many variables that come into play. Sure, you could figure out the thread pitch and how much that moves the rear sight blade, but the distance to the target, barrel length, front sight height and sight picture all come into play.
 
Value, caliber, barrel length, etc in sight adjustment? Adjusted sights over 50+yrs & not used these terms. Know where hits on paper print & using proper screwdiver turn windage/elevation screweither clock or counter clock several clicks. Watch to see sight base or blade move. Remember # clicks turned. Shoot paper to check print up, down, right, left. From there you'll figure it out. May have over simplified or don't get the question. Ain't rocket science...no disrespect intended.

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While with a rifle one click may be say 1" at 100 yrds it does not work that way with revolvers. When you fire a revolver it begins to rotate up immediately upon firing. The longer the barrel the more time the bullet is in the barrel and the higher the muzzle angle when bullet leaves. Same applies to heavier slower bullets. Opposite for shorter barrels or faster bullets. As all rear sights have the same screw pitch and number of clickes for a full revolution, how much elevation change you get per click depends on barrel length and load as well as how firmly you grip the revolver and you wrist strength.

I have huge hands and need 2X gloves, my wrists are also very large. I always have pr0blems getting my guns to zero with the standard factory blade as even with the rear sight bottomed out the usually shoot low for me unless I install a shorter rear sight blade. Most other people shoot high with a revolver I zeroed for me.

Rifles do not do this nearly as bad because the stock anchors the rear of the gun to your shoulder and that severely dampens the rotation

I have made 2 revolvers into stocked carbines with over 16" barrels. On both of them I had to remove a majority of the front sight height compared to the blade on the same caliber revolver because of this.
 
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Fixed sight adjustment is with your on board computer (brain) transmitted to hand & eye to sights. Better known as 'Kentucky windage.

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The thread pitch is 80 threads per inch for windage and elevation. There are 6 clicks per turn on both. One full turn moves the sight - 1" divided x 80 = .0125. One click moves the sight about .002. The sight radius on a Smith is approximately barrel length + 2".

Using the knowledge of sight radius and sight blade movement, you can trig out how much the sight will move the point of impact (POI) at any given distance. All you really need to know is how far you're changing from where you were hitting to where you want to hit. While all the other factors come into play, they will be more or less consistent for a good shooter.

For example, shooting a 6" gun on the bench with sandbags at 25 yards, one click will move the POI .225, or about 1/4". A full turn would be .225 x 6 = 1.350, or about 1-3/8".
 
Nice math Protocall. Having adjustable sight guns from 3" to 6", 22lr to 500 mag I just do the turn turn and see what happens method. If I fire a group 2" low and the tighten the screw a full turn and it moves 1 3/4" up I know another 1/2 turn will get it.
 
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Protocol is on track, there are mathematical formulas that can be used to determine with pretty solid reliability, how far each click of the rear sight moves the impact. I may have even seen in my old bullseye competition days a chart that gave you this specific info, and lots of competitors would tape a copy of the data chart inside the pistol range box for quick reference. Outside of formal competition where absolutely precise repeatable adjustments were/ are required, I use the method of just keep clicking until it put shots where you want them. On most revolvers it won’t take long or require much ammo, and usually is a one time event, unless you change bullet weight and velocity often.
 
Protocall Design is only partially correct. While his math regarding rear sight movement per click or full-turn is correct there is also sight radius and other variables to consider!

An adjustable sighted 2" gun will see more adjustment than a 6" or 8 3/8" gun since a specific movement of the rear sight will cause a greater angular (movement of group) difference between the center-line of the bore and line-of-sight with the shorter barrelled guns than it will with longer barrels.

The distance to the target will also affect the amount of change to point-of-impact on the target because the ratio of sight radius to distance to target has to be considered in the total calculation. The change at 50 yards will be twice what it is at 25 yards for a specific movement of the rear sight.

As another poster stated, there are several variables that must all be considered!
 
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Protocall_Design said:
The thread pitch is 80 threads per inch for windage and elevation. There are 6 clicks per turn on both. One full turn moves the sight - 1" divided x 80 = .0125. One click moves the sight about .002. The sight radius on a Smith is approximately barrel length + 2".

Using the knowledge of sight radius and sight blade movement, you can trig out how much the sight will move the point of impact (POI) at any given distance. All you really need to know is how far you're changing from where you were hitting to where you want to hit. While all the other factors come into play, they will be more or less consistent for a good shooter.

For example, shooting a 6" gun on the bench with sandbags at 25 yards, one click will move the POI .225, or about 1/4". A full turn would be .225 x 6 = 1.350, or about 1-3/8".
Click to expand...

As the great silhouetteer Ken Hale explained to me: It's all about ratios!

Protocall Design's explanation is pretty close to being exactly correct, given that the clicks aren't as exact as is mathematically calculated.

One slight built in error is that the rear sight blade rear isn't directly over the centerline of the screw and the pivot point may shift slightly with very large elevation changes due to where the bottom of the sight touches the top strap shifts forward as the sight goes up. Not really important until you go past 100 yards, and probably lost in the increase in the group size.

Given the assumption that the change per click really does move every time (1/80)*(1/6), then the rear sight does indeed move slightly more than 0.002" (0.002083repeating"). Again, in the real world it's not that repeatable!

That leaves only three variables affecting Point of Impact change due to sight movement:

"X" in inches= POI change in inches per click.
"Y" in inches= sight radius in inches from the rear of the front to the rear of the rear sight blade.
"Z" in yards= distance from the front sight to the target in yards. (The equation will convert yards to inches, i.e., 100 yards is converted internally to 3600 inches.)

Zo!:

X= (1/(80*6))*(Z*36))/Y
Sorry, it looks much tidier if you can show the equation in two lines. Or, even better, stacked "four high".

Or: X=((1/480)*(Z*36))/Y=(0.075*Z)/Y

Since "Y" doesn't change for a particular S&W revolver, it is pretty simple once you make it a constant to figure out the POI change per click for any distance. If "Y" is 10.375" on a 8 3/8" barreled revolver then:

X=0.00723*Z

(I think, trying to type this is much more confusing than doing it on paper for some reason.)

Which means a bit less than 3/4" POI change per click at 100yds. And 3/16" change at 25!

It really works. I made a tool with a dial indicator that sits on the topstrap to see actual changes whilst making rear sight elevation changes so I don't have to worry about theoretical click values, but counting clicks works pretty well under time pressure at a match.

FYI, my usual sight settings go from 25, 50, 75, and 100yds, OR 50m, 100m, 150m and 200m.
Happily, I have several four position front sight equipped revolvers which don't have clicks but can be measured easily with dial calipers.

And if you want to really start getting crazy there's the "roller coaster" windage change screw which messes with your elevation setting....Arggh!
 
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Good grief... more algorithms, physics, ratios, rotations...just load'er up and go shoot...🥸

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Am I the only person who just sometimes wonders "if"? Didnt say I needed or had to know to sight in any of my 9 revolvers, they happen to shoot just fine, even with me pulling the trigger.��
I just wondered if there was such a thing. I guess the internet isnt the sphere to think out loud. A simple no would have been fine with me.
However, people like Protocalldesign,as always, and jaymoore, gives a precise, professional response. Thank you to those types.
 
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