Revolver Adjustable Rear Sight Question

[Butte]

Does anyone know the thread pitch on the elevation and windage adjustment screws, and whether they've changed from the old to new style rear sight? I have a number of Smiths with various barrel lengths, and I'd like to calculate the point-of-impact movement per click of sight screw rotation.

 

[handgunner356]

I would think you would need to know each barrel length and load used on each gun in order to make the calculations.

 

[tomcatt51]

Does anyone know the thread pitch on the elevation and windage adjustment screws, and whether they've changed from the old to new style rear sight?

Old style and new style use the same "adjusters".

 

[Butte]

I've recently determined that the elevation and windage screws are both 3-80. Hence, there will be approximately 0.012" of movement per turn or 0.002" per click.

Using these numbers and doing a little math, the approximate point of impact change for a 6" barrel is 0.25"/click at 25 yards. The shorter sight radius on at 4" barrel gun will result in approximately .33"/click change at 25 yards. The elevation change will actually be slightly larger than the windage change, because the elevation screw is not directly under the sight leaf but ahead of it.

I hope this information is useful and helps save some ammo when sighting in a new gun or re-sighting when changing loads. Smith would save us all a lot of trouble and expense if they included it in their current manuals.

 

[TheKySharpshooter]

Thank you Butte for posting this. I'm taking my 14-4 to the tange for the first time Sunday and I was really wondering how many clicks I would have to deal with. IHMSA Field Pistol goes out to 100m so I had no idea what to expect, but using a ballistics calculator and this rough info at least I have an approximate in my head. Thank you again, I'll let you know how it turns out