I just don't get adjustable tang sights

[DavidC]

I understand the idea of having a sight set as far back as possible, but I don't understand how the vernier tang sights can be reliably accurate, because as you adjust the height of the rear sight, you're surely going to shift slightly left or right of the front sight. That would mean you would have to constantly re-zero the sight if you adjusted the height for a different range. The only way past this would be if the sight is positioned so the bore axis and sight adjustment axis are perfectly perpendicular with the shooting plane.

Am I missing something, or are you setting the sight, both elevation and windage, for a specific range? Can you ever adjust elevation without also needing to significantly adjust windage? 

[dadybear1]

I THINK(JUST ME) YOU ARE ON TARGET... LIKE A SCOPE  THE FURTHER THE RANGE THE MORE OUT SIDE FACTORS INFLUENCE ACCURACY( WIND-EARTH REV-HEAT/COLD ETC)

[snapper]

When I setup a tang sight for long range shooting, I use a level on the staff to get it square with the rifle.   The last one I did I used a digital "tilt" gauge that is for a setting your table saw blades to be square.    I think it went to .001.   

I keep a book with my sight settings in it for each rifle.  Setting the tang sight for yardage is fairly straight forward, when it comes to left and right you simply crank on your windage settings.   For target work you have sighters before you go for score, so it is not a big deal (normally) to crank in some left or right.   Throughout the match I am cranking on left and right and up and down as conditions change.

It is rare that even your elevation settings are right on from one match to another, but as long as you are fairly close. that is what the vertical and horizontal adjustments are for.


Fleener

[DavidC]

Do some of the sights have a tilt adjustment for the staff, or do you shim the base in some way to level it?

[Bob Roller]

The sights I  have made for BPCR and the one long range muzzle loader I made all had a 4x48 screw to adjust tilt.On the muzzle loader the staff folded  forward and on the BPCR's all folded back to allow for cleaning.Only one had windage and the rest had an adjustable front sight with a bubble level.
Bob Roller

[snapper]

I shim with either aluminum from a beverage can or brass.   I have never tried a screw.

Some rifles have a bubble level on the front sights which helps keep the gun in the right position.   

Fleener

[Bob Roller]

I describe myself as being a "Half of a bubble off of level" .The sights I made for my own guns had the tilt adjustment screw incorporated in the design and was a 6x40 thread. 40TPI is the accepted number for precise measurement and one full turn will give
.025 or 4 turns for .100.
Bob Roller

[Dphariss]

Yes they have to have the staff vertical to in relation to the rifle.
And yes they work really well.
The verniers can be adjusted to about .001 elevation even though calibrated to .01.
If they did not work people would not pay several hundred dollars for the good ones. But they are not exactly needed for a RB hunting rifle.  The tallest staff MVA Soule LR sights are almost $600.
The simpler versions are over 300 even for the short staff.
https://montanavintagearms.com/sights/

[danny]

I thought this was interesting

[Not English]

I'll second that notion. There's a lot of info in that video, plus it's well presented.

[Bob Roller]

These are my favorite muzzle loading rifles followed closely by the plain as the loading rod SMR's in flint or percussion.In 1962 I bought a fine Whitworth Semi-military match rifle from E.M.Farris Gun Shop for $300 and used it for 11 years and sold it for $1200 in 1973.
It had Whitworth Patent sights and an Alex Henry barrel instead of the hex bore normally seen on a Whitworth.The number was C760 and
I have been told it is back in England.Lynton McKenzie had it for a while and didn't believe I used it for 11 years because it was still in the same condition as when I bought it. It had a superb Brazier "4 pin"lock with sliding safety in front of the hammer.That lock stirred my interest in making them but didn't do it until 1987.I borrowed several locks from Lynton afterward and he said the big reason he would loan them to me was that the condition of the Whitworth after my 11 years of owning it.If a good milling machine is available these sights are not that hard to make and the 40 threads per inch taps and dies can be bought from any GOOD industrial supply shop.
Thanks fof posting the video.
Bob Roller

[Sharpsman]

As to being left/right of a particular zero when raising the rear tang the procedure to compensate for this is to shim the base of the rear sight such that when the elevation is extended to maximum the sight follows a vertical line as near to center of a drawn vertical line as possible. Use of a plumb bob to establish a vertical line of about 36" length is used and then the rifle is zeroed say from 50 yards to be hitting at the bottom of the drawn line. This being established, the vertical adjustment is then raised say to a point half way up the sight staff and a shot is fired. The method is to then raise the rear sight staff to maximum and have shots fired to stay on or as close  to the vertical line as possible.....all of this being done also requires that a level bubble is utilized throughout this procedure!

[Dphariss]

Not only does the staff need to be vertical in relation to the bore but the rifle must be level when aimed. Thus the bubble level  on front sights. These are still used on modern LR brass suppository rifles with scopes. If you do not hold the rifle level then the windage will be off from shot to shot and its magnified  as the rear aperture gets raised higher at long range.
In the game I shoot the most ammo in shooting with the rifle canted results in any significant elevation changes requiring windage changes as well on the sights/scope. This said even on a hunting rifle an aperture rear sight with a suitable sized aperture is very useful. But “ghost ring” rears are useless when the light gets low.